diff --git a/.clang-tidy.yml b/.clang-tidy.yml
index 91a83733eb..539acdd7c3 100644
--- a/.clang-tidy.yml
+++ b/.clang-tidy.yml
@@ -14,4 +14,5 @@ Checks: >-
   -clang-diagnostic-nullability-extension,
   bugprone-suspicious-realloc-usage,
   misc-const-correctness,
-  portability-*
+  portability-*,
+  readability-named-parameter
diff --git a/lib/altsvc.c b/lib/altsvc.c
index 64bfec420b..3d3de12700 100644
--- a/lib/altsvc.c
+++ b/lib/altsvc.c
@@ -329,12 +329,12 @@ CURLcode Curl_altsvc_ctrl(struct Curl_easy *data, const long ctrl)
  * Curl_altsvc_cleanup() frees an altsvc cache instance and all associated
  * resources.
  */
-void Curl_altsvc_cleanup(struct altsvcinfo **altsvcp)
+void Curl_altsvc_cleanup(struct altsvcinfo **asi)
 {
-  if(*altsvcp) {
+  if(*asi) {
     struct Curl_llist_node *e;
     struct Curl_llist_node *n;
-    struct altsvcinfo *altsvc = *altsvcp;
+    struct altsvcinfo *altsvc = *asi;
     for(e = Curl_llist_head(&altsvc->list); e; e = n) {
       struct altsvc *as = Curl_node_elem(e);
       n = Curl_node_next(e);
@@ -342,7 +342,7 @@ void Curl_altsvc_cleanup(struct altsvcinfo **altsvcp)
     }
     curlx_free(altsvc->filename);
     curlx_free(altsvc);
-    *altsvcp = NULL; /* clear the pointer */
+    *asi = NULL; /* clear the pointer */
   }
 }
 
@@ -350,21 +350,21 @@ void Curl_altsvc_cleanup(struct altsvcinfo **altsvcp)
  * Curl_altsvc_save() writes the altsvc cache to a file.
  */
 CURLcode Curl_altsvc_save(struct Curl_easy *data,
-                          struct altsvcinfo *altsvc, const char *file)
+                          struct altsvcinfo *asi, const char *file)
 {
   CURLcode result = CURLE_OK;
   FILE *out;
   char *tempstore = NULL;
 
-  if(!altsvc)
+  if(!asi)
     /* no cache activated */
     return CURLE_OK;
 
   /* if not new name is given, use the one we stored from the load */
-  if(!file && altsvc->filename)
-    file = altsvc->filename;
+  if(!file && asi->filename)
+    file = asi->filename;
 
-  if((altsvc->flags & CURLALTSVC_READONLYFILE) || !file || !file[0])
+  if((asi->flags & CURLALTSVC_READONLYFILE) || !file || !file[0])
     /* marked as read-only, no file or zero length filename */
     return CURLE_OK;
 
@@ -375,7 +375,7 @@ CURLcode Curl_altsvc_save(struct Curl_easy *data,
     fputs("# Your alt-svc cache. https://curl.se/docs/alt-svc.html\n"
           "# This file was generated by libcurl! Edit at your own risk.\n",
           out);
-    for(e = Curl_llist_head(&altsvc->list); e; e = n) {
+    for(e = Curl_llist_head(&asi->list); e; e = n) {
       struct altsvc *as = Curl_node_elem(e);
       n = Curl_node_next(e);
       result = altsvc_out(as, out);
diff --git a/lib/altsvc.h b/lib/altsvc.h
index 85da8cceb9..2931af452b 100644
--- a/lib/altsvc.h
+++ b/lib/altsvc.h
@@ -55,10 +55,10 @@ CURLcode Curl_altsvc_load(struct altsvcinfo *asi, const char *file);
 CURLcode Curl_altsvc_save(struct Curl_easy *data,
                           struct altsvcinfo *asi, const char *file);
 CURLcode Curl_altsvc_ctrl(struct Curl_easy *data, const long ctrl);
-void Curl_altsvc_cleanup(struct altsvcinfo **altsvc);
+void Curl_altsvc_cleanup(struct altsvcinfo **asi);
 CURLcode Curl_altsvc_parse(struct Curl_easy *data,
-                           struct altsvcinfo *altsvc, const char *value,
-                           enum alpnid srcalpn, const char *srchost,
+                           struct altsvcinfo *asi, const char *value,
+                           enum alpnid srcalpnid, const char *srchost,
                            unsigned short srcport);
 bool Curl_altsvc_lookup(struct altsvcinfo *asi,
                         enum alpnid srcalpnid, const char *srchost,
diff --git a/lib/asyn-ares.c b/lib/asyn-ares.c
index 755550f73d..a9e697ff60 100644
--- a/lib/asyn-ares.c
+++ b/lib/asyn-ares.c
@@ -380,14 +380,14 @@ out:
  * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  */
 CURLcode Curl_async_await(struct Curl_easy *data,
-                          struct Curl_dns_entry **entry)
+                          struct Curl_dns_entry **dns)
 {
   struct async_ares_ctx *ares = &data->state.async.ares;
   CURLcode result = CURLE_OK;
   timediff_t timeout_ms;
 
-  DEBUGASSERT(entry);
-  *entry = NULL; /* clear on entry */
+  DEBUGASSERT(dns);
+  *dns = NULL; /* clear on entry */
 
   timeout_ms = Curl_timeleft_ms(data);
   if(timeout_ms < 0) {
@@ -426,7 +426,7 @@ CURLcode Curl_async_await(struct Curl_easy *data,
     if(Curl_ares_perform(ares->channel, call_timeout_ms) < 0)
       return CURLE_UNRECOVERABLE_POLL;
 
-    result = Curl_async_is_resolved(data, entry);
+    result = Curl_async_is_resolved(data, dns);
     if(result || data->state.async.done)
       break;
 
@@ -449,7 +449,7 @@ CURLcode Curl_async_await(struct Curl_easy *data,
   /* Operation complete, if the lookup was successful we now have the entry
      in the cache. */
   data->state.async.done = TRUE;
-  *entry = data->state.async.dns;
+  *dns = data->state.async.dns;
 
   if(result)
     ares_cancel(ares->channel);
diff --git a/lib/asyn-thrdd.c b/lib/asyn-thrdd.c
index 0e06db22ca..e616a8cee2 100644
--- a/lib/asyn-thrdd.c
+++ b/lib/asyn-thrdd.c
@@ -101,8 +101,8 @@ void Curl_async_global_cleanup(void)
 #endif
 }
 
-static void async_thrdd_destroy(struct Curl_easy *);
-static void async_thrdd_shutdown(struct Curl_easy *);
+static void async_thrdd_destroy(struct Curl_easy *data);
+static void async_thrdd_shutdown(struct Curl_easy *data);
 
 CURLcode Curl_async_get_impl(struct Curl_easy *data, void **impl)
 {
@@ -552,11 +552,11 @@ void Curl_async_thrdd_destroy(struct Curl_easy *data)
  * This is the version for resolves-in-a-thread.
  */
 CURLcode Curl_async_await(struct Curl_easy *data,
-                          struct Curl_dns_entry **entry)
+                          struct Curl_dns_entry **dns)
 {
   struct async_thrdd_ctx *thrdd = &data->state.async.thrdd;
   if(thrdd->addr)
-    return asyn_thrdd_await(data, thrdd->addr, entry);
+    return asyn_thrdd_await(data, thrdd->addr, dns);
   return CURLE_FAILED_INIT;
 }
 
diff --git a/lib/asyn.h b/lib/asyn.h
index 12d3e1c338..68628f90c0 100644
--- a/lib/asyn.h
+++ b/lib/asyn.h
@@ -70,7 +70,7 @@ void Curl_async_global_cleanup(void);
  * Get the resolver implementation instance (c-ares channel) or NULL
  * for passing to application callback.
  */
-CURLcode Curl_async_get_impl(struct Curl_easy *easy, void **impl);
+CURLcode Curl_async_get_impl(struct Curl_easy *data, void **impl);
 
 /* Curl_async_pollset()
  *
@@ -106,7 +106,7 @@ CURLcode Curl_async_is_resolved(struct Curl_easy *data,
  * CURLE_OPERATION_TIMEDOUT if a time-out occurred, or other errors.
  */
 CURLcode Curl_async_await(struct Curl_easy *data,
-                          struct Curl_dns_entry **dnsentry);
+                          struct Curl_dns_entry **dns);
 
 /*
  * Curl_async_getaddrinfo() - when using this resolver
diff --git a/lib/cf-h1-proxy.h b/lib/cf-h1-proxy.h
index e48d827825..6544ec58d0 100644
--- a/lib/cf-h1-proxy.h
+++ b/lib/cf-h1-proxy.h
@@ -27,7 +27,7 @@
 
 #if !defined(CURL_DISABLE_PROXY) && !defined(CURL_DISABLE_HTTP)
 
-CURLcode Curl_cf_h1_proxy_insert_after(struct Curl_cfilter *cf,
+CURLcode Curl_cf_h1_proxy_insert_after(struct Curl_cfilter *cf_at,
                                        struct Curl_easy *data);
 
 extern struct Curl_cftype Curl_cft_h1_proxy;
diff --git a/lib/cfilters.c b/lib/cfilters.c
index db8efcf2fe..4905418fa3 100644
--- a/lib/cfilters.c
+++ b/lib/cfilters.c
@@ -136,22 +136,22 @@ void Curl_conn_cf_discard_chain(struct Curl_cfilter **pcf,
 }
 
 void Curl_conn_cf_discard_all(struct Curl_easy *data,
-                              struct connectdata *conn, int index)
+                              struct connectdata *conn, int sockindex)
 {
-  Curl_conn_cf_discard_chain(&conn->cfilter[index], data);
+  Curl_conn_cf_discard_chain(&conn->cfilter[sockindex], data);
 }
 
-void Curl_conn_close(struct Curl_easy *data, int index)
+void Curl_conn_close(struct Curl_easy *data, int sockindex)
 {
   struct Curl_cfilter *cf;
 
   DEBUGASSERT(data->conn);
   /* it is valid to call that without filters being present */
-  cf = data->conn->cfilter[index];
+  cf = data->conn->cfilter[sockindex];
   if(cf) {
     cf->cft->do_close(cf, data);
   }
-  Curl_shutdown_clear(data, index);
+  Curl_shutdown_clear(data, sockindex);
 }
 
 CURLcode Curl_conn_shutdown(struct Curl_easy *data, int sockindex, bool *done)
@@ -209,14 +209,14 @@ CURLcode Curl_conn_shutdown(struct Curl_easy *data, int sockindex, bool *done)
   return result;
 }
 
-CURLcode Curl_cf_recv(struct Curl_easy *data, int num, char *buf,
+CURLcode Curl_cf_recv(struct Curl_easy *data, int sockindex, char *buf,
                       size_t len, size_t *pnread)
 {
   struct Curl_cfilter *cf;
 
   DEBUGASSERT(data);
   DEBUGASSERT(data->conn);
-  cf = data->conn->cfilter[num];
+  cf = data->conn->cfilter[sockindex];
   while(cf && !cf->connected)
     cf = cf->next;
   if(cf)
@@ -227,19 +227,19 @@ CURLcode Curl_cf_recv(struct Curl_easy *data, int num, char *buf,
   return CURLE_FAILED_INIT;
 }
 
-CURLcode Curl_cf_send(struct Curl_easy *data, int num,
-                      const uint8_t *mem, size_t len, bool eos,
+CURLcode Curl_cf_send(struct Curl_easy *data, int sockindex,
+                      const uint8_t *buf, size_t len, bool eos,
                       size_t *pnwritten)
 {
   struct Curl_cfilter *cf;
 
   DEBUGASSERT(data);
   DEBUGASSERT(data->conn);
-  cf = data->conn->cfilter[num];
+  cf = data->conn->cfilter[sockindex];
   while(cf && !cf->connected)
     cf = cf->next;
   if(cf) {
-    return cf->cft->do_send(cf, data, mem, len, eos, pnwritten);
+    return cf->cft->do_send(cf, data, buf, len, eos, pnwritten);
   }
   failf(data, "send: no filter connected");
   DEBUGASSERT(0);
@@ -328,17 +328,17 @@ out:
 
 void Curl_conn_cf_add(struct Curl_easy *data,
                       struct connectdata *conn,
-                      int index,
+                      int sockindex,
                       struct Curl_cfilter *cf)
 {
   DEBUGASSERT(conn);
   DEBUGASSERT(!cf->conn);
   DEBUGASSERT(!cf->next);
 
-  cf->next = conn->cfilter[index];
+  cf->next = conn->cfilter[sockindex];
   cf->conn = conn;
-  cf->sockindex = index;
-  conn->cfilter[index] = cf;
+  cf->sockindex = sockindex;
+  conn->cfilter[sockindex] = cf;
   CURL_TRC_CF(data, cf, "added");
 }
 
@@ -1060,23 +1060,23 @@ int Curl_conn_sockindex(struct Curl_easy *data, curl_socket_t sockfd)
 }
 
 CURLcode Curl_conn_recv(struct Curl_easy *data, int sockindex,
-                        char *buf, size_t blen, size_t *pnread)
+                        char *buf, size_t len, size_t *pnread)
 {
   DEBUGASSERT(data);
   DEBUGASSERT(data->conn);
   if(!CONN_SOCK_IDX_VALID(sockindex))
     return CURLE_BAD_FUNCTION_ARGUMENT;
   if(data && data->conn && data->conn->recv[sockindex])
-    return data->conn->recv[sockindex](data, sockindex, buf, blen, pnread);
+    return data->conn->recv[sockindex](data, sockindex, buf, len, pnread);
   *pnread = 0;
   return CURLE_FAILED_INIT;
 }
 
 CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
-                        const void *buf, size_t blen, bool eos,
+                        const void *buf, size_t len, bool eos,
                         size_t *pnwritten)
 {
-  size_t write_len = blen;
+  size_t write_len = len;
 
   DEBUGASSERT(data);
   DEBUGASSERT(data->conn);
@@ -1094,7 +1094,7 @@ CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
     }
   }
 #endif
-  if(write_len != blen)
+  if(write_len != len)
     eos = FALSE;
   if(data && data->conn && data->conn->send[sockindex])
     return data->conn->send[sockindex](data, sockindex, buf, write_len, eos,
diff --git a/lib/cfilters.h b/lib/cfilters.h
index 9faf01de75..cb52f3265f 100644
--- a/lib/cfilters.h
+++ b/lib/cfilters.h
@@ -312,8 +312,7 @@ void Curl_conn_cf_discard_chain(struct Curl_cfilter **pcf,
  * Remove and destroy all filters at chain `sockindex` on connection `conn`.
  */
 void Curl_conn_cf_discard_all(struct Curl_easy *data,
-                              struct connectdata *conn,
-                              int sockindex);
+                              struct connectdata *conn, int sockindex);
 
 CURLcode Curl_conn_cf_connect(struct Curl_cfilter *cf,
                               struct Curl_easy *data,
@@ -608,15 +607,14 @@ int Curl_conn_sockindex(struct Curl_easy *data, curl_socket_t sockfd);
  * Will return CURLE_AGAIN iff blocked on receiving.
  */
 CURLcode Curl_conn_recv(struct Curl_easy *data, int sockindex,
-                        char *buf, size_t buffersize,
-                        size_t *pnread);
+                        char *buf, size_t len, size_t *pnread);
 
 /*
  * Send data on the connection, using FIRSTSOCKET/SECONDARYSOCKET.
  * Will return CURLE_AGAIN iff blocked on sending.
  */
 CURLcode Curl_conn_send(struct Curl_easy *data, int sockindex,
-                        const void *buf, size_t blen, bool eos,
+                        const void *buf, size_t len, bool eos,
                         size_t *pnwritten);
 
 /**
diff --git a/lib/conncache.h b/lib/conncache.h
index 9b392af05c..d8626ae692 100644
--- a/lib/conncache.h
+++ b/lib/conncache.h
@@ -68,7 +68,7 @@ void Curl_cpool_init(struct cpool *cpool,
                      size_t size);
 
 /* Destroy all connections and free all members */
-void Curl_cpool_destroy(struct cpool *connc);
+void Curl_cpool_destroy(struct cpool *cpool);
 
 /* Init the transfer to be used within its connection pool.
  * Assigns `data->id`. */
diff --git a/lib/connect.h b/lib/connect.h
index f2b9911073..071b4329c1 100644
--- a/lib/connect.h
+++ b/lib/connect.h
@@ -32,7 +32,7 @@ struct ip_quadruple;
 struct Curl_str;
 
 enum alpnid Curl_alpn2alpnid(const unsigned char *name, size_t len);
-enum alpnid Curl_str2alpnid(const struct Curl_str *str);
+enum alpnid Curl_str2alpnid(const struct Curl_str *cstr);
 
 /* generic function that returns how much time there is left to run, according
    to the timeouts set */
@@ -76,7 +76,7 @@ bool Curl_addr2string(struct sockaddr *sa, curl_socklen_t salen,
                       char *addr, uint16_t *port);
 
 /*
- * Curl_conncontrol() marks the end of a connection/stream. The 'closeit'
+ * Curl_conncontrol() marks the end of a connection/stream. The 'ctrl'
  * argument specifies if it is the end of a connection or a stream.
  *
  * For stream-based protocols (such as HTTP/2), a stream close will not cause
@@ -92,7 +92,7 @@ bool Curl_addr2string(struct sockaddr *sa, curl_socklen_t salen,
 #define CONNCTRL_STREAM 2
 
 void Curl_conncontrol(struct connectdata *conn,
-                      int closeit
+                      int ctrl
 #if defined(DEBUGBUILD) && defined(CURLVERBOSE)
                       , const char *reason
 #endif
diff --git a/lib/cookie.h b/lib/cookie.h
index cbc7b748fc..fabd04d398 100644
--- a/lib/cookie.h
+++ b/lib/cookie.h
@@ -111,15 +111,18 @@ struct connectdata;
 
 bool Curl_secure_context(struct connectdata *conn, const char *host);
 CURLcode Curl_cookie_add(struct Curl_easy *data,
-                         struct CookieInfo *c, bool header,
-                         bool noexpiry, const char *lineptr,
-                         const char *domain, const char *path,
+                         struct CookieInfo *ci,
+                         bool httpheader,
+                         bool noexpire,
+                         const char *lineptr,
+                         const char *domain,
+                         const char *path,
                          bool secure) WARN_UNUSED_RESULT;
 CURLcode Curl_cookie_getlist(struct Curl_easy *data, struct connectdata *conn,
                              bool *okay, const char *host,
                              struct Curl_llist *list) WARN_UNUSED_RESULT;
-void Curl_cookie_clearall(struct CookieInfo *cookies);
-void Curl_cookie_clearsess(struct CookieInfo *cookies);
+void Curl_cookie_clearall(struct CookieInfo *ci);
+void Curl_cookie_clearsess(struct CookieInfo *ci);
 
 #if defined(CURL_DISABLE_HTTP) || defined(CURL_DISABLE_COOKIES)
 #define Curl_cookie_list(x) NULL
@@ -130,7 +133,7 @@ void Curl_cookie_clearsess(struct CookieInfo *cookies);
 #define Curl_flush_cookies(x, y) Curl_nop_stmt
 #else
 void Curl_flush_cookies(struct Curl_easy *data, bool cleanup);
-void Curl_cookie_cleanup(struct CookieInfo *c);
+void Curl_cookie_cleanup(struct CookieInfo *ci);
 struct CookieInfo *Curl_cookie_init(void);
 struct curl_slist *Curl_cookie_list(struct Curl_easy *data);
 CURLcode Curl_cookie_loadfiles(struct Curl_easy *data) WARN_UNUSED_RESULT;
diff --git a/lib/cshutdn.h b/lib/cshutdn.h
index 79c95cca59..9030474032 100644
--- a/lib/cshutdn.h
+++ b/lib/cshutdn.h
@@ -41,12 +41,12 @@ void Curl_cshutdn_run_once(struct Curl_easy *data,
                            bool *done);
 
 /* Terminates the connection, e.g. closes and destroys it.
- * If `run_shutdown` is TRUE, the shutdown will be run once before
+ * If `do_shutdown` is TRUE, the shutdown will be run once before
  * terminating it.
  * Takes ownership of `conn`. */
 void Curl_cshutdn_terminate(struct Curl_easy *data,
                             struct connectdata *conn,
-                            bool run_shutdown);
+                            bool do_shutdown);
 
 /* A `cshutdown` is always owned by a multi handle to maintain
  * the connections to be shut down. It registers timers and
diff --git a/lib/curl_addrinfo.c b/lib/curl_addrinfo.c
index 1b8dd7a225..63540c168d 100644
--- a/lib/curl_addrinfo.c
+++ b/lib/curl_addrinfo.c
@@ -404,19 +404,19 @@ static CURLcode ip2addr(struct Curl_addrinfo **addrp, int af,
  * Given an IPv4 or IPv6 dotted string address, this converts it to a proper
  * allocated Curl_addrinfo struct and returns it.
  */
-CURLcode Curl_str2addr(const char *address, int port,
+CURLcode Curl_str2addr(const char *dotted, int port,
                        struct Curl_addrinfo **addrp)
 {
   struct in_addr in;
-  if(curlx_inet_pton(AF_INET, address, &in) > 0)
+  if(curlx_inet_pton(AF_INET, dotted, &in) > 0)
     /* This is a dotted IP address 123.123.123.123-style */
-    return ip2addr(addrp, AF_INET, &in, address, port);
+    return ip2addr(addrp, AF_INET, &in, dotted, port);
 #ifdef USE_IPV6
   {
     struct in6_addr in6;
-    if(curlx_inet_pton(AF_INET6, address, &in6) > 0)
+    if(curlx_inet_pton(AF_INET6, dotted, &in6) > 0)
       /* This is a dotted IPv6 address ::1-style */
-      return ip2addr(addrp, AF_INET6, &in6, address, port);
+      return ip2addr(addrp, AF_INET6, &in6, dotted, port);
   }
 #endif
   return CURLE_BAD_FUNCTION_ARGUMENT; /* bad input format */
diff --git a/lib/curl_hmac.h b/lib/curl_hmac.h
index 4759ff6ec6..b9f218fac9 100644
--- a/lib/curl_hmac.h
+++ b/lib/curl_hmac.h
@@ -57,10 +57,10 @@ struct HMAC_context {
 struct HMAC_context *Curl_HMAC_init(const struct HMAC_params *hashparams,
                                     const unsigned char *key,
                                     unsigned int keylen);
-int Curl_HMAC_update(struct HMAC_context *context,
+int Curl_HMAC_update(struct HMAC_context *ctxt,
                      const unsigned char *data,
                      unsigned int len);
-int Curl_HMAC_final(struct HMAC_context *context, unsigned char *result);
+int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *output);
 
 CURLcode Curl_hmacit(const struct HMAC_params *hashparams,
                      const unsigned char *key, const size_t keylen,
diff --git a/lib/curl_md5.h b/lib/curl_md5.h
index 16272c7591..042c5f59ae 100644
--- a/lib/curl_md5.h
+++ b/lib/curl_md5.h
@@ -58,7 +58,7 @@ CURLcode Curl_md5it(unsigned char *output, const unsigned char *input,
 
 struct MD5_context *Curl_MD5_init(const struct MD5_params *md5params);
 CURLcode Curl_MD5_update(struct MD5_context *context,
-                         const unsigned char *data,
+                         const unsigned char *input,
                          unsigned int len);
 CURLcode Curl_MD5_final(struct MD5_context *context, unsigned char *result);
 
diff --git a/lib/curl_sha256.h b/lib/curl_sha256.h
index 0aaa4126f4..bc1512e6e8 100644
--- a/lib/curl_sha256.h
+++ b/lib/curl_sha256.h
@@ -37,7 +37,7 @@ extern const struct HMAC_params Curl_HMAC_SHA256;
 #define CURL_SHA256_DIGEST_LENGTH 32 /* fixed size */
 #endif
 
-CURLcode Curl_sha256it(unsigned char *outbuffer, const unsigned char *input,
+CURLcode Curl_sha256it(unsigned char *output, const unsigned char *input,
                        const size_t len);
 
 #endif
diff --git a/lib/curlx/strdup.h b/lib/curlx/strdup.h
index 1e6bc19814..3e17fdee63 100644
--- a/lib/curlx/strdup.h
+++ b/lib/curlx/strdup.h
@@ -28,6 +28,6 @@
 #ifdef _WIN32
 wchar_t *curlx_wcsdup(const wchar_t *src);  /* for curlx_tcsdup() */
 #endif
-void *curlx_memdup(const void *src, size_t buffer_length);
+void *curlx_memdup(const void *src, size_t length);
 void *curlx_memdup0(const char *src, size_t length);
 #endif /* HEADER_CURLX_STRDUP_H */
diff --git a/lib/curlx/strparse.h b/lib/curlx/strparse.h
index ae8fd19d95..eb3d491595 100644
--- a/lib/curlx/strparse.h
+++ b/lib/curlx/strparse.h
@@ -98,7 +98,8 @@ int curlx_str_cmp(struct Curl_str *str, const char *check);
 
 int curlx_str_nudge(struct Curl_str *str, size_t num);
 
-int curlx_str_cspn(const char **linep, struct Curl_str *out, const char *cspn);
+int curlx_str_cspn(const char **linep, struct Curl_str *out,
+                   const char *reject);
 void curlx_str_trimblanks(struct Curl_str *out);
 void curlx_str_passblanks(const char **linep);
 
diff --git a/lib/curlx/warnless.h b/lib/curlx/warnless.h
index 8a62ccf6a7..3d0341e418 100644
--- a/lib/curlx/warnless.h
+++ b/lib/curlx/warnless.h
@@ -69,6 +69,6 @@ bool curlx_sotouz_fits(curl_off_t sonum, size_t *puznum);
 
 /* Convert a long to size_t, return FALSE if negative or too large
  * and set 0 */
-bool curlx_sltouz(long sznum, size_t *puznum);
+bool curlx_sltouz(long slnum, size_t *puznum);
 
 #endif /* HEADER_CURL_WARNLESS_H */
diff --git a/lib/doh.h b/lib/doh.h
index 0dc6a3f2a4..0deafc7fde 100644
--- a/lib/doh.h
+++ b/lib/doh.h
@@ -114,7 +114,7 @@ CURLcode Curl_doh(struct Curl_easy *data, const char *hostname,
                   int port, int ip_version);
 
 CURLcode Curl_doh_is_resolved(struct Curl_easy *data,
-                              struct Curl_dns_entry **dns);
+                              struct Curl_dns_entry **dnsp);
 
 #define DOH_MAX_ADDR  24
 #define DOH_MAX_CNAME 4
diff --git a/lib/ftp.c b/lib/ftp.c
index 310e03ec87..cbfe825628 100644
--- a/lib/ftp.c
+++ b/lib/ftp.c
@@ -168,8 +168,8 @@ static CURLcode ftp_nb_type(struct Curl_easy *data,
                             struct ftp_conn *ftpc,
                             struct FTP *ftp,
                             bool ascii, ftpstate newstate);
-static CURLcode getftpresponse(struct Curl_easy *data, size_t *nread,
-                               int *ftpcode);
+static CURLcode getftpresponse(struct Curl_easy *data, size_t *nreadp,
+                               int *ftpcodep);
 
 static void freedirs(struct ftp_conn *ftpc)
 {
@@ -629,7 +629,7 @@ static CURLcode ftp_readresp(struct Curl_easy *data,
  */
 static CURLcode getftpresponse(struct Curl_easy *data,
                                size_t *nreadp, /* return number of bytes
-                                                   read */
+                                                  read */
                                int *ftpcodep) /* return the ftp-code */
 {
   /*
diff --git a/lib/ftplistparser.h b/lib/ftplistparser.h
index afb90dee4c..5d7aa492ba 100644
--- a/lib/ftplistparser.h
+++ b/lib/ftplistparser.h
@@ -37,7 +37,7 @@ CURLcode Curl_ftp_parselist_geterror(struct ftp_parselist_data *pl_data);
 
 struct ftp_parselist_data *Curl_ftp_parselist_data_alloc(void);
 
-void Curl_ftp_parselist_data_free(struct ftp_parselist_data **pl_data);
+void Curl_ftp_parselist_data_free(struct ftp_parselist_data **parserp);
 
 /* list of wildcard process states */
 typedef enum {
diff --git a/lib/hmac.c b/lib/hmac.c
index 9080588341..10d7c1d03b 100644
--- a/lib/hmac.c
+++ b/lib/hmac.c
@@ -99,11 +99,11 @@ fail:
 }
 
 int Curl_HMAC_update(struct HMAC_context *ctxt,
-                     const unsigned char *ptr,
+                     const unsigned char *data,
                      unsigned int len)
 {
   /* Update first hash calculation. */
-  ctxt->hash->hupdate(ctxt->hashctxt1, ptr, len);
+  ctxt->hash->hupdate(ctxt->hashctxt1, data, len);
   return 0;
 }
 
@@ -143,7 +143,7 @@ int Curl_HMAC_final(struct HMAC_context *ctxt, unsigned char *output)
  */
 CURLcode Curl_hmacit(const struct HMAC_params *hashparams,
                      const unsigned char *key, const size_t keylen,
-                     const unsigned char *buf, const size_t buflen,
+                     const unsigned char *data, const size_t datalen,
                      unsigned char *output)
 {
   struct HMAC_context *ctxt =
@@ -153,7 +153,7 @@ CURLcode Curl_hmacit(const struct HMAC_params *hashparams,
     return CURLE_OUT_OF_MEMORY;
 
   /* Update the digest with the given challenge */
-  Curl_HMAC_update(ctxt, buf, curlx_uztoui(buflen));
+  Curl_HMAC_update(ctxt, data, curlx_uztoui(datalen));
 
   /* Finalise the digest */
   Curl_HMAC_final(ctxt, output);
diff --git a/lib/hostip.c b/lib/hostip.c
index cfa7995dba..597c77173c 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -1015,20 +1015,20 @@ CURLcode Curl_resolv_blocking(struct Curl_easy *data,
                               const char *hostname,
                               int port,
                               int ip_version,
-                              struct Curl_dns_entry **dnsentry)
+                              struct Curl_dns_entry **entry)
 {
   CURLcode result;
   DEBUGASSERT(hostname && *hostname);
-  *dnsentry = NULL;
-  result = Curl_resolv(data, hostname, port, ip_version, FALSE, dnsentry);
+  *entry = NULL;
+  result = Curl_resolv(data, hostname, port, ip_version, FALSE, entry);
   switch(result) {
   case CURLE_OK:
-    DEBUGASSERT(*dnsentry);
+    DEBUGASSERT(*entry);
     return CURLE_OK;
   case CURLE_AGAIN:
-    DEBUGASSERT(!*dnsentry);
-    result = Curl_async_await(data, dnsentry);
-    if(result || !*dnsentry) {
+    DEBUGASSERT(!*entry);
+    result = Curl_async_await(data, entry);
+    if(result || !*entry) {
       /* close the connection, since we cannot return failure here without
          cleaning up this connection properly. */
       connclose(data->conn, "async resolve failed");
diff --git a/lib/hostip.h b/lib/hostip.h
index e70eac841b..6c7f1291b2 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -86,18 +86,18 @@ CURLcode Curl_resolv(struct Curl_easy *data,
                      int port,
                      int ip_version,
                      bool allowDOH,
-                     struct Curl_dns_entry **dnsentry);
+                     struct Curl_dns_entry **entry);
 
 CURLcode Curl_resolv_blocking(struct Curl_easy *data,
                               const char *hostname,
                               int port,
                               int ip_version,
-                              struct Curl_dns_entry **dnsentry);
+                              struct Curl_dns_entry **entry);
 
 CURLcode Curl_resolv_timeout(struct Curl_easy *data,
                              const char *hostname, int port,
                              int ip_version,
-                             struct Curl_dns_entry **dnsentry,
+                             struct Curl_dns_entry **entry,
                              timediff_t timeoutms);
 
 #ifdef USE_IPV6
@@ -118,7 +118,7 @@ void Curl_resolv_unlink(struct Curl_easy *data,
                         struct Curl_dns_entry **pdns);
 
 /* init a new dns cache */
-void Curl_dnscache_init(struct Curl_dnscache *dns, size_t hashsize);
+void Curl_dnscache_init(struct Curl_dnscache *dns, size_t size);
 
 void Curl_dnscache_destroy(struct Curl_dnscache *dns);
 
@@ -133,14 +133,14 @@ struct Curl_addrinfo *Curl_ipv4_resolve_r(const char *hostname, int port);
 
 CURLcode Curl_once_resolved(struct Curl_easy *data,
                             struct Curl_dns_entry *dns,
-                            bool *protocol_connect);
+                            bool *protocol_done);
 
 /*
  * Curl_printable_address() returns a printable version of the 1st address
  * given in the 'ip' argument. The result will be stored in the buf that is
  * bufsize bytes big.
  */
-void Curl_printable_address(const struct Curl_addrinfo *ip,
+void Curl_printable_address(const struct Curl_addrinfo *ai,
                             char *buf, size_t bufsize);
 
 /*
diff --git a/lib/hsts.h b/lib/hsts.h
index e2c9922f18..e0f6363bb3 100644
--- a/lib/hsts.h
+++ b/lib/hsts.h
@@ -49,7 +49,7 @@ struct hsts {
 struct hsts *Curl_hsts_init(void);
 void Curl_hsts_cleanup(struct hsts **hp);
 CURLcode Curl_hsts_parse(struct hsts *h, const char *hostname,
-                         const char *sts);
+                         const char *header);
 struct stsentry *Curl_hsts(struct hsts *h, const char *hostname,
                            size_t hlen, bool subdomain);
 CURLcode Curl_hsts_save(struct Curl_easy *data, struct hsts *h,
diff --git a/lib/http2.c b/lib/http2.c
index b0717f9ff6..1381041c56 100644
--- a/lib/http2.c
+++ b/lib/http2.c
@@ -670,7 +670,7 @@ char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
 /*
  * push header access function. Only to be used from within the push callback
  */
-char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
+char *curl_pushheader_byname(struct curl_pushheaders *h, const char *name)
 {
   struct h2_stream_ctx *stream;
   size_t len;
@@ -681,17 +681,17 @@ char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
      the header, but header == ":" must be rejected. If we have ':' in
      the middle of header, it could be matched in middle of the value,
      this is because we do prefix match.*/
-  if(!h || !GOOD_EASY_HANDLE(h->data) || !header || !header[0] ||
-     !strcmp(header, ":") || strchr(header + 1, ':'))
+  if(!h || !GOOD_EASY_HANDLE(h->data) || !name || !name[0] ||
+     !strcmp(name, ":") || strchr(name + 1, ':'))
     return NULL;
 
   stream = h->stream;
   if(!stream)
     return NULL;
 
-  len = strlen(header);
+  len = strlen(name);
   for(i = 0; i < stream->push_headers_used; i++) {
-    if(!strncmp(header, stream->push_headers[i], len)) {
+    if(!strncmp(name, stream->push_headers[i], len)) {
       /* sub-match, make sure that it is followed by a colon */
       if(stream->push_headers[i][len] != ':')
         continue;
@@ -3001,10 +3001,10 @@ char *curl_pushheader_bynum(struct curl_pushheaders *h, size_t num)
   return NULL;
 }
 
-char *curl_pushheader_byname(struct curl_pushheaders *h, const char *header)
+char *curl_pushheader_byname(struct curl_pushheaders *h, const char *name)
 {
   (void)h;
-  (void)header;
+  (void)name;
   return NULL;
 }
 
diff --git a/lib/http2.h b/lib/http2.h
index 5e545b2349..a14c8485cc 100644
--- a/lib/http2.h
+++ b/lib/http2.h
@@ -55,7 +55,7 @@ CURLcode Curl_http2_switch_at(struct Curl_cfilter *cf, struct Curl_easy *data);
 
 CURLcode Curl_http2_upgrade(struct Curl_easy *data,
                             struct connectdata *conn, int sockindex,
-                            const char *ptr, size_t nread);
+                            const char *mem, size_t nread);
 
 void *Curl_nghttp2_malloc(size_t size, void *user_data);
 void Curl_nghttp2_free(void *ptr, void *user_data);
diff --git a/lib/idn.h b/lib/idn.h
index 42613af509..90d8e811b1 100644
--- a/lib/idn.h
+++ b/lib/idn.h
@@ -30,7 +30,7 @@ CURLcode Curl_idnconvert_hostname(struct hostname *host);
 #define USE_IDN
 void Curl_free_idnconverted_hostname(struct hostname *host);
 CURLcode Curl_idn_decode(const char *input, char **output);
-CURLcode Curl_idn_encode(const char *input, char **output);
+CURLcode Curl_idn_encode(const char *puny, char **output);
 #else
 #define Curl_free_idnconverted_hostname(x)
 #define Curl_idn_decode(x) NULL
diff --git a/lib/llist.h b/lib/llist.h
index 1d73db1719..31c5b45ed3 100644
--- a/lib/llist.h
+++ b/lib/llist.h
@@ -52,9 +52,9 @@ struct Curl_llist_node {
 
 void Curl_llist_init(struct Curl_llist *, Curl_llist_dtor);
 void Curl_llist_insert_next(struct Curl_llist *, struct Curl_llist_node *,
-                            const void *, struct Curl_llist_node *node);
+                            const void *, struct Curl_llist_node *ne);
 void Curl_llist_append(struct Curl_llist *, const void *,
-                       struct Curl_llist_node *node);
+                       struct Curl_llist_node *ne);
 void Curl_node_remove(struct Curl_llist_node *);
 void Curl_llist_destroy(struct Curl_llist *, void *);
 
@@ -74,7 +74,7 @@ void *Curl_node_elem(struct Curl_llist_node *n);
 
 /* Remove the node from the list and return the custom data
  * from a Curl_llist_node. Will NOT invoke a registered `dtor`. */
-void *Curl_node_take_elem(struct Curl_llist_node *);
+void *Curl_node_take_elem(struct Curl_llist_node *e);
 
 /* Curl_node_next() returns the next element in a list from a given
    Curl_llist_node */
diff --git a/lib/mime.c b/lib/mime.c
index 7f350ae7e0..fdac2e0f41 100644
--- a/lib/mime.c
+++ b/lib/mime.c
@@ -1270,18 +1270,18 @@ CURLcode curl_mime_filename(curl_mimepart *part, const char *filename)
 }
 
 /* Set mime part content from memory data. */
-CURLcode curl_mime_data(curl_mimepart *part, const char *ptr, size_t datasize)
+CURLcode curl_mime_data(curl_mimepart *part, const char *data, size_t datasize)
 {
   if(!part)
     return CURLE_BAD_FUNCTION_ARGUMENT;
 
   cleanup_part_content(part);
 
-  if(ptr) {
+  if(data) {
     if(datasize == CURL_ZERO_TERMINATED)
-      datasize = strlen(ptr);
+      datasize = strlen(data);
 
-    part->data = curlx_memdup0(ptr, datasize);
+    part->data = curlx_memdup0(data, datasize);
     if(!part->data)
       return CURLE_OUT_OF_MEMORY;
 
diff --git a/lib/multi.c b/lib/multi.c
index 66456fe928..6b1e9d62d1 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -3607,11 +3607,11 @@ void Curl_expire(struct Curl_easy *data, timediff_t milli, expire_id id)
  * Removes the expire timer. Marks it as done.
  *
  */
-void Curl_expire_done(struct Curl_easy *data, expire_id eid)
+void Curl_expire_done(struct Curl_easy *data, expire_id id)
 {
   /* remove the timer, if there */
-  multi_deltimeout(data, eid);
-  CURL_TRC_TIMER(data, eid, "cleared");
+  multi_deltimeout(data, id);
+  CURL_TRC_TIMER(data, id, "cleared");
 }
 
 /*
diff --git a/lib/multiif.h b/lib/multiif.h
index 0252b2dfd9..f6cb3294e5 100644
--- a/lib/multiif.h
+++ b/lib/multiif.h
@@ -47,7 +47,7 @@ void Curl_multi_connchanged(struct Curl_multi *multi);
 /* Internal version of curl_multi_init() accepts size parameters for the
    socket, connection and dns hashes */
 struct Curl_multi *Curl_multi_handle(uint32_t xfer_table_size,
-                                     size_t hashsize,
+                                     size_t ev_hashsize,
                                      size_t chashsize,
                                      size_t dnssize,
                                      size_t sesssize);
diff --git a/lib/netrc.c b/lib/netrc.c
index baabe917a7..031660c531 100644
--- a/lib/netrc.c
+++ b/lib/netrc.c
@@ -464,14 +464,14 @@ NETRCcode Curl_parsenetrc(struct store_netrc *store, const char *host,
   return retcode;
 }
 
-void Curl_netrc_init(struct store_netrc *s)
+void Curl_netrc_init(struct store_netrc *store)
 {
-  curlx_dyn_init(&s->filebuf, MAX_NETRC_FILE);
-  s->loaded = FALSE;
+  curlx_dyn_init(&store->filebuf, MAX_NETRC_FILE);
+  store->loaded = FALSE;
 }
-void Curl_netrc_cleanup(struct store_netrc *s)
+void Curl_netrc_cleanup(struct store_netrc *store)
 {
-  curlx_dyn_free(&s->filebuf);
-  s->loaded = FALSE;
+  curlx_dyn_free(&store->filebuf);
+  store->loaded = FALSE;
 }
 #endif
diff --git a/lib/netrc.h b/lib/netrc.h
index 99ddc6253e..061e1e438b 100644
--- a/lib/netrc.h
+++ b/lib/netrc.h
@@ -45,12 +45,12 @@ typedef enum {
 } NETRCcode;
 
 const char *Curl_netrc_strerror(NETRCcode ret);
-void Curl_netrc_init(struct store_netrc *s);
-void Curl_netrc_cleanup(struct store_netrc *s);
+void Curl_netrc_init(struct store_netrc *store);
+void Curl_netrc_cleanup(struct store_netrc *store);
 
-NETRCcode Curl_parsenetrc(struct store_netrc *s, const char *host,
+NETRCcode Curl_parsenetrc(struct store_netrc *store, const char *host,
                           char **loginp, char **passwordp,
-                          const char *filename);
+                          const char *netrcfile);
 /* Assume: (*passwordp)[0]=0, host[0] != 0.
  * If (*loginp)[0] = 0, search for login and password within a machine
  * section in the netrc.
diff --git a/lib/parsedate.c b/lib/parsedate.c
index 29b0932d7c..744efc4ed3 100644
--- a/lib/parsedate.c
+++ b/lib/parsedate.c
@@ -558,11 +558,11 @@ static int parsedate(const char *date, time_t *output)
 }
 #endif
 
-time_t curl_getdate(const char *p, const time_t *now)
+time_t curl_getdate(const char *p, const time_t *unused)
 {
   time_t parsed = -1;
   int rc = parsedate(p, &parsed);
-  (void)now; /* legacy argument from the past that we ignore */
+  (void)unused; /* legacy argument from the past that we ignore */
 
   if(rc == PARSEDATE_OK) {
     if(parsed == (time_t)-1)
diff --git a/lib/parsedate.h b/lib/parsedate.h
index a6ee43a5d4..ea136bd301 100644
--- a/lib/parsedate.h
+++ b/lib/parsedate.h
@@ -30,6 +30,6 @@ extern const char * const Curl_month[12];
    TIME_T_MAX in case the parsed time value was too big, instead of an
    error. */
 
-int Curl_getdate_capped(const char *p, time_t *store);
+int Curl_getdate_capped(const char *p, time_t *tp);
 
 #endif /* HEADER_CURL_PARSEDATE_H */
diff --git a/lib/request.h b/lib/request.h
index 389ae4d8b1..3a2dd0de98 100644
--- a/lib/request.h
+++ b/lib/request.h
@@ -178,7 +178,7 @@ void Curl_req_hard_reset(struct SingleRequest *req, struct Curl_easy *data);
  * @param httpversion version used in request (09, 10, 11, etc.)
  * @return CURLE_OK (on blocking with *pnwritten == 0) or error.
  */
-CURLcode Curl_req_send(struct Curl_easy *data, struct dynbuf *buf,
+CURLcode Curl_req_send(struct Curl_easy *data, struct dynbuf *req,
                        unsigned char httpversion);
 
 /**
diff --git a/lib/select.h b/lib/select.h
index 268ae7cecf..68150451c4 100644
--- a/lib/select.h
+++ b/lib/select.h
@@ -71,7 +71,8 @@ struct pollfd {
    therefore defined here */
 #define CURL_CSELECT_IN2 (CURL_CSELECT_ERR << 1)
 
-int Curl_socket_check(curl_socket_t readfd, curl_socket_t readfd2,
+int Curl_socket_check(curl_socket_t readfd0,
+                      curl_socket_t readfd1,
                       curl_socket_t writefd,
                       timediff_t timeout_ms);
 #define SOCKET_READABLE(x, z)                               \
diff --git a/lib/sendf.c b/lib/sendf.c
index fcb67933d3..c8b0e28eea 100644
--- a/lib/sendf.c
+++ b/lib/sendf.c
@@ -373,7 +373,7 @@ static CURLcode do_init_writer_stack(struct Curl_easy *data)
    The defines are in sendf.h of course.
  */
 CURLcode Curl_client_write(struct Curl_easy *data,
-                           int type, const char *buf, size_t blen)
+                           int type, const char *buf, size_t len)
 {
   CURLcode result;
 
@@ -394,9 +394,9 @@ CURLcode Curl_client_write(struct Curl_easy *data,
     DEBUGASSERT(data->req.writer_stack);
   }
 
-  result = Curl_cwriter_write(data, data->req.writer_stack, type, buf, blen);
+  result = Curl_cwriter_write(data, data->req.writer_stack, type, buf, len);
   CURL_TRC_WRITE(data, "client_write(type=%x, len=%zu) -> %d",
-                 type, blen, result);
+                 type, len, result);
   return result;
 }
 
diff --git a/lib/sendf.h b/lib/sendf.h
index 1521ccb0f8..952ed4c123 100644
--- a/lib/sendf.h
+++ b/lib/sendf.h
@@ -58,7 +58,7 @@ struct Curl_easy;
  * Write `len` bytes at `prt` to the client. `type` indicates what
  * kind of data is being written.
  */
-CURLcode Curl_client_write(struct Curl_easy *data, int type, const char *ptr,
+CURLcode Curl_client_write(struct Curl_easy *data, int type, const char *buf,
                            size_t len) WARN_UNUSED_RESULT;
 
 /**
@@ -140,7 +140,7 @@ struct Curl_cwriter {
  */
 CURLcode Curl_cwriter_create(struct Curl_cwriter **pwriter,
                              struct Curl_easy *data,
-                             const struct Curl_cwtype *ce_handler,
+                             const struct Curl_cwtype *cwt,
                              Curl_cwriter_phase phase);
 
 /**
@@ -298,7 +298,7 @@ void Curl_creader_clear_eos(struct Curl_easy *data,
  */
 CURLcode Curl_creader_create(struct Curl_creader **preader,
                              struct Curl_easy *data,
-                             const struct Curl_crtype *cr_handler,
+                             const struct Curl_crtype *crt,
                              Curl_creader_phase phase);
 
 /**
diff --git a/lib/setopt.h b/lib/setopt.h
index 0dd60c785f..c421f5c5e5 100644
--- a/lib/setopt.h
+++ b/lib/setopt.h
@@ -34,7 +34,7 @@ CURLcode Curl_setopt_SSLVERSION(struct Curl_easy *data, CURLoption option,
 CURLcode Curl_setstropt(char **charp, const char *s) WARN_UNUSED_RESULT;
 CURLcode Curl_setblobopt(struct curl_blob **blobp,
                          const struct curl_blob *blob) WARN_UNUSED_RESULT;
-CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list arg)
+CURLcode Curl_vsetopt(struct Curl_easy *data, CURLoption option, va_list param)
   WARN_UNUSED_RESULT;
 
 #endif /* HEADER_CURL_SETOPT_H */
diff --git a/lib/sha256.c b/lib/sha256.c
index 8e581fec78..e35aa30649 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -452,14 +452,14 @@ static void my_sha256_final(unsigned char *out, void *ctx)
  * Returns CURLE_OK on success.
  */
 CURLcode Curl_sha256it(unsigned char *output, const unsigned char *input,
-                       const size_t length)
+                       const size_t len)
 {
   CURLcode result;
   my_sha256_ctx ctx;
 
   result = my_sha256_init(&ctx);
   if(!result) {
-    my_sha256_update(&ctx, input, curlx_uztoui(length));
+    my_sha256_update(&ctx, input, curlx_uztoui(len));
     my_sha256_final(output, &ctx);
   }
   return result;
diff --git a/lib/splay.h b/lib/splay.h
index 9ed96f63e4..c6623f2ef0 100644
--- a/lib/splay.h
+++ b/lib/splay.h
@@ -42,7 +42,7 @@ struct Curl_tree *Curl_splay(const struct curltime *pkey,
 
 struct Curl_tree *Curl_splayinsert(const struct curltime *pkey,
                                    struct Curl_tree *t,
-                                   struct Curl_tree *newnode);
+                                   struct Curl_tree *node);
 
 struct Curl_tree *Curl_splaygetbest(const struct curltime *pkey,
                                     struct Curl_tree *t,
diff --git a/lib/strcase.h b/lib/strcase.h
index 35f726c3ee..54299812be 100644
--- a/lib/strcase.h
+++ b/lib/strcase.h
@@ -36,6 +36,6 @@ void Curl_strntoupper(char *dest, const char *src, size_t n);
 void Curl_strntolower(char *dest, const char *src, size_t n);
 
 bool Curl_safecmp(const char *a, const char *b);
-int Curl_timestrcmp(const char *first, const char *second);
+int Curl_timestrcmp(const char *a, const char *b);
 
 #endif /* HEADER_CURL_STRCASE_H */
diff --git a/lib/strequal.c b/lib/strequal.c
index 98cecdc244..e712691bdc 100644
--- a/lib/strequal.c
+++ b/lib/strequal.c
@@ -73,23 +73,23 @@ static int ncasecompare(const char *first, const char *second, size_t max)
  */
 
 /* --- public function --- */
-int curl_strequal(const char *first, const char *second)
+int curl_strequal(const char *s1, const char *s2)
 {
-  if(first && second)
+  if(s1 && s2)
     /* both pointers point to something then compare them */
-    return casecompare(first, second);
+    return casecompare(s1, s2);
 
   /* if both pointers are NULL then treat them as equal */
-  return NULL == first && NULL == second;
+  return NULL == s1 && NULL == s2;
 }
 
 /* --- public function --- */
-int curl_strnequal(const char *first, const char *second, size_t max)
+int curl_strnequal(const char *s1, const char *s2, size_t n)
 {
-  if(first && second)
+  if(s1 && s2)
     /* both pointers point to something then compare them */
-    return ncasecompare(first, second, max);
+    return ncasecompare(s1, s2, n);
 
   /* if both pointers are NULL then treat them as equal if max is non-zero */
-  return NULL == first && NULL == second && max;
+  return NULL == s1 && NULL == s2 && n;
 }
diff --git a/lib/uint-table.h b/lib/uint-table.h
index 3fc7e34ef4..398a26a648 100644
--- a/lib/uint-table.h
+++ b/lib/uint-table.h
@@ -47,7 +47,7 @@ void Curl_uint32_tbl_init(struct uint32_tbl *tbl,
 
 /* Resize the table to change capacity `nmax`. When `nmax` is reduced,
  * all present entries with key equal or larger to `nmax` are removed. */
-CURLcode Curl_uint32_tbl_resize(struct uint32_tbl *tbl, uint32_t nmax);
+CURLcode Curl_uint32_tbl_resize(struct uint32_tbl *tbl, uint32_t nrows);
 
 /* Destroy the table, freeing all entries. */
 void Curl_uint32_tbl_destroy(struct uint32_tbl *tbl);
diff --git a/lib/url.h b/lib/url.h
index 1e44ebe43b..c4cd762fb8 100644
--- a/lib/url.h
+++ b/lib/url.h
@@ -36,14 +36,16 @@ void Curl_init_userdefined(struct Curl_easy *data);
 void Curl_freeset(struct Curl_easy *data);
 CURLcode Curl_uc_to_curlcode(CURLUcode uc);
 CURLcode Curl_close(struct Curl_easy **datap); /* opposite of Curl_open() */
-CURLcode Curl_connect(struct Curl_easy *, bool *async, bool *protocol_connect);
+CURLcode Curl_connect(struct Curl_easy *data,
+                      bool *asyncp,
+                      bool *protocol_done);
 CURLcode Curl_setup_conn(struct Curl_easy *data,
                          struct Curl_dns_entry *dns,
                          bool *protocol_done);
 void Curl_conn_free(struct Curl_easy *data, struct connectdata *conn);
 CURLcode Curl_parse_login_details(const char *login, const size_t len,
-                                  char **userptr, char **passwdptr,
-                                  char **optionsptr);
+                                  char **userp, char **passwdp,
+                                  char **optionsp);
 
 /* Attach/Clear/Get meta data for an easy handle. Needs to provide
  * a destructor, will be automatically called when the easy handle
diff --git a/lib/vauth/cleartext.c b/lib/vauth/cleartext.c
index fc8a6ebd51..d9b11d3cb3 100644
--- a/lib/vauth/cleartext.c
+++ b/lib/vauth/cleartext.c
@@ -81,14 +81,14 @@ CURLcode Curl_auth_create_plain_message(const char *authzid,
  *
  * Parameters:
  *
- * valuep  [in]     - The username or user's password.
+ * value   [in]     - The username or user's password.
  * out     [out]    - The result storage.
  *
  * Returns void.
  */
-void Curl_auth_create_login_message(const char *valuep, struct bufref *out)
+void Curl_auth_create_login_message(const char *value, struct bufref *out)
 {
-  Curl_bufref_set(out, valuep, strlen(valuep), NULL);
+  Curl_bufref_set(out, value, strlen(value), NULL);
 }
 
 /*
diff --git a/lib/vauth/vauth.h b/lib/vauth/vauth.h
index 312bd8da5a..1649dc6832 100644
--- a/lib/vauth/vauth.h
+++ b/lib/vauth/vauth.h
@@ -110,7 +110,7 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
                                               const char *userp,
                                               const char *passwdp,
                                               const unsigned char *request,
-                                              const unsigned char *uri,
+                                              const unsigned char *uripath,
                                               struct digestdata *digest,
                                               char **outptr, size_t *outlen);
 
@@ -150,7 +150,7 @@ CURLcode Curl_auth_gsasl_token(struct Curl_easy *data,
                                struct bufref *out);
 
 /* This is used to clean up the gsasl specific data */
-void Curl_auth_gsasl_cleanup(struct gsasldata *digest);
+void Curl_auth_gsasl_cleanup(struct gsasldata *gsasl);
 #endif
 
 #ifdef USE_NTLM
@@ -199,13 +199,13 @@ CURLcode Curl_auth_create_ntlm_type1_message(struct Curl_easy *data,
                                              const char *userp,
                                              const char *passwdp,
                                              const char *service,
-                                             const char *host,
+                                             const char *hostname,
                                              struct ntlmdata *ntlm,
                                              struct bufref *out);
 
 /* This is used to decode a base64 encoded NTLM type-2 message */
 CURLcode Curl_auth_decode_ntlm_type2_message(struct Curl_easy *data,
-                                             const struct bufref *type2,
+                                             const struct bufref *type2ref,
                                              struct ntlmdata *ntlm);
 
 /* This is used to generate a base64 encoded NTLM type-3 message */
diff --git a/lib/vssh/vssh.c b/lib/vssh/vssh.c
index 7bb06a8222..d3abe57b35 100644
--- a/lib/vssh/vssh.c
+++ b/lib/vssh/vssh.c
@@ -285,19 +285,19 @@ fail:
 }
 
 CURLcode Curl_ssh_range(struct Curl_easy *data,
-                        const char *p, curl_off_t filesize,
+                        const char *range, curl_off_t filesize,
                         curl_off_t *startp, curl_off_t *sizep)
 {
   curl_off_t from, to;
   int to_t;
-  int from_t = curlx_str_number(&p, &from, CURL_OFF_T_MAX);
+  int from_t = curlx_str_number(&range, &from, CURL_OFF_T_MAX);
   if(from_t == STRE_OVERFLOW)
     return CURLE_RANGE_ERROR;
-  curlx_str_passblanks(&p);
-  (void)curlx_str_single(&p, '-');
+  curlx_str_passblanks(&range);
+  (void)curlx_str_single(&range, '-');
 
-  to_t = curlx_str_numblanks(&p, &to);
-  if((to_t == STRE_OVERFLOW) || (to_t && from_t) || *p)
+  to_t = curlx_str_numblanks(&range, &to);
+  if((to_t == STRE_OVERFLOW) || (to_t && from_t) || *range)
     return CURLE_RANGE_ERROR;
 
   if(from_t) {
diff --git a/lib/vtls/hostcheck.h b/lib/vtls/hostcheck.h
index d62c721352..0b4384cb7d 100644
--- a/lib/vtls/hostcheck.h
+++ b/lib/vtls/hostcheck.h
@@ -28,7 +28,7 @@
 #if defined(USE_OPENSSL) || defined(USE_SCHANNEL)
 
 /* returns TRUE if there is a match */
-bool Curl_cert_hostcheck(const char *match_pattern, size_t matchlen,
+bool Curl_cert_hostcheck(const char *match, size_t matchlen,
                          const char *hostname, size_t hostlen);
 
 #endif
diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 0e039386c1..b72b8fc34f 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -917,10 +917,9 @@ static bool is_pkcs11_uri(const char *string)
 
 #endif
 
-static CURLcode ossl_set_engine(struct Curl_easy *data, const char *engine);
+static CURLcode ossl_set_engine(struct Curl_easy *data, const char *name);
 #ifdef OPENSSL_HAS_PROVIDERS
-static CURLcode ossl_set_provider(struct Curl_easy *data,
-                                  const char *provider);
+static CURLcode ossl_set_provider(struct Curl_easy *data, const char *iname);
 #endif
 
 static int use_certificate_blob(SSL_CTX *ctx, const struct curl_blob *blob,
diff --git a/lib/vtls/openssl.h b/lib/vtls/openssl.h
index 02522550d9..b99ac8a3a5 100644
--- a/lib/vtls/openssl.h
+++ b/lib/vtls/openssl.h
@@ -106,7 +106,7 @@ CURLcode Curl_ossl_ctx_init(struct ossl_ctx *octx,
                             struct Curl_cfilter *cf,
                             struct Curl_easy *data,
                             struct ssl_peer *peer,
-                            const struct alpn_spec *alpns,
+                            const struct alpn_spec *alpns_requested,
                             Curl_ossl_ctx_setup_cb *cb_setup,
                             void *cb_user_data,
                             Curl_ossl_new_session_cb *cb_new_session,
@@ -138,7 +138,7 @@ CURLcode Curl_ossl_ctx_configure(struct Curl_cfilter *cf,
 CURLcode Curl_ossl_add_session(struct Curl_cfilter *cf,
                                struct Curl_easy *data,
                                const char *ssl_peer_key,
-                               SSL_SESSION *ssl_sessionid,
+                               SSL_SESSION *session,
                                int ietf_tls_id,
                                const char *alpn,
                                unsigned char *quic_tp,
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index 8df23a6660..fcaa173daa 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -679,12 +679,11 @@ CURLcode Curl_ssl_push_certinfo_len(struct Curl_easy *data,
 
 /* get length bytes of randomness */
 CURLcode Curl_ssl_random(struct Curl_easy *data,
-                         unsigned char *entropy,
-                         size_t length)
+                         unsigned char *buffer, size_t length)
 {
   DEBUGASSERT(length == sizeof(int));
   if(Curl_ssl->random)
-    return Curl_ssl->random(data, entropy, length);
+    return Curl_ssl->random(data, buffer, length);
   else
     return CURLE_NOT_BUILT_IN;
 }
diff --git a/lib/vtls/vtls.h b/lib/vtls/vtls.h
index 8b04c11101..12ae3a4c73 100644
--- a/lib/vtls/vtls.h
+++ b/lib/vtls/vtls.h
@@ -178,8 +178,8 @@ CURLcode Curl_ssl_push_certinfo(struct Curl_easy *data, int certnum,
 /* Functions to be used by SSL library adaptation functions */
 
 /* get N random bytes into the buffer */
-CURLcode Curl_ssl_random(struct Curl_easy *data, unsigned char *buffer,
-                         size_t length);
+CURLcode Curl_ssl_random(struct Curl_easy *data,
+                         unsigned char *buffer, size_t length);
 /* Check pinned public key. */
 CURLcode Curl_pin_peer_pubkey(struct Curl_easy *data,
                               const char *pinnedpubkey,
diff --git a/lib/vtls/vtls_scache.c b/lib/vtls/vtls_scache.c
index 60300c7646..f937a1db9f 100644
--- a/lib/vtls/vtls_scache.c
+++ b/lib/vtls/vtls_scache.c
@@ -914,7 +914,7 @@ CURLcode Curl_ssl_scache_add_obj(struct Curl_cfilter *cf,
                                  struct Curl_easy *data,
                                  const char *ssl_peer_key,
                                  void *sobj,
-                                 Curl_ssl_scache_obj_dtor *sobj_free)
+                                 Curl_ssl_scache_obj_dtor *sobj_dtor_cb)
 {
   struct Curl_ssl_scache *scache = cf_ssl_scache_get(data);
   struct ssl_primary_config *conn_config = Curl_ssl_cf_get_primary_config(cf);
@@ -922,7 +922,7 @@ CURLcode Curl_ssl_scache_add_obj(struct Curl_cfilter *cf,
   CURLcode result;
 
   DEBUGASSERT(sobj);
-  DEBUGASSERT(sobj_free);
+  DEBUGASSERT(sobj_dtor_cb);
 
   if(!scache) {
     result = CURLE_BAD_FUNCTION_ARGUMENT;
@@ -935,12 +935,12 @@ CURLcode Curl_ssl_scache_add_obj(struct Curl_cfilter *cf,
     goto out;
   }
 
-  cf_ssl_scache_peer_set_obj(peer, sobj, sobj_free);
+  cf_ssl_scache_peer_set_obj(peer, sobj, sobj_dtor_cb);
   sobj = NULL;  /* peer took ownership */
 
 out:
-  if(sobj && sobj_free)
-    sobj_free(sobj);
+  if(sobj && sobj_dtor_cb)
+    sobj_dtor_cb(sobj);
   return result;
 }
 
diff --git a/lib/ws.c b/lib/ws.c
index 5c37236315..60465611bb 100644
--- a/lib/ws.c
+++ b/lib/ws.c
@@ -622,7 +622,7 @@ static CURLcode ws_enc_send(struct Curl_easy *data,
                             size_t buflen,
                             curl_off_t fragsize,
                             unsigned int flags,
-                            size_t *sent);
+                            size_t *pnsent);
 static CURLcode ws_enc_add_pending(struct Curl_easy *data,
                                    struct websocket *ws);
 
diff --git a/lib/ws.h b/lib/ws.h
index d4d6d46f3a..757eae0f0f 100644
--- a/lib/ws.h
+++ b/lib/ws.h
@@ -34,7 +34,8 @@ extern const struct Curl_scheme Curl_scheme_wss;
 #define CURL_META_PROTO_WS_CONN   "meta:proto:ws:conn"
 
 CURLcode Curl_ws_request(struct Curl_easy *data, struct dynbuf *req);
-CURLcode Curl_ws_accept(struct Curl_easy *data, const char *mem, size_t len);
+CURLcode Curl_ws_accept(struct Curl_easy *data,
+                        const char *mem, size_t nread);
 
 #else
 #define Curl_ws_request(x, y) CURLE_OK
diff --git a/src/tool_easysrc.h b/src/tool_easysrc.h
index f9ddacfc37..f37ce4ba86 100644
--- a/src/tool_easysrc.h
+++ b/src/tool_easysrc.h
@@ -39,7 +39,7 @@ extern int easysrc_mime_count;  /* Number of curl_mime variables */
 extern int easysrc_slist_count; /* Number of curl_slist variables */
 
 extern CURLcode easysrc_init(void);
-extern CURLcode easysrc_add(struct slist_wc **plist, const char *bupf);
+extern CURLcode easysrc_add(struct slist_wc **plist, const char *line);
 extern CURLcode easysrc_addf(struct slist_wc **plist,
                              const char *fmt, ...) CURL_PRINTF(2, 3);
 extern CURLcode easysrc_perform(void);
diff --git a/src/tool_getpass.c b/src/tool_getpass.c
index 99ded8f4c5..68a16cab3e 100644
--- a/src/tool_getpass.c
+++ b/src/tool_getpass.c
@@ -162,7 +162,7 @@ static bool ttyecho(bool enable, int fd)
 }
 
 char *getpass_r(const char *prompt, /* prompt to display */
-                char *password,     /* buffer to store password in */
+                char *buffer,       /* buffer to store password in */
                 size_t buflen)      /* size of buffer to store password in */
 {
   ssize_t nread;
@@ -174,11 +174,11 @@ char *getpass_r(const char *prompt, /* prompt to display */
   disabled = ttyecho(FALSE, fd); /* disable terminal echo */
 
   fputs(prompt, tool_stderr);
-  nread = read(fd, password, buflen);
+  nread = read(fd, buffer, buflen);
   if(nread > 0)
-    password[--nread] = '\0'; /* null-terminate where enter is stored */
+    buffer[--nread] = '\0'; /* null-terminate where enter is stored */
   else
-    password[0] = '\0'; /* got nothing */
+    buffer[0] = '\0'; /* got nothing */
 
   if(disabled) {
     /* if echo actually was disabled, add a newline */
@@ -189,7 +189,7 @@ char *getpass_r(const char *prompt, /* prompt to display */
   if(STDIN_FILENO != fd)
     curlx_close(fd);
 
-  return password; /* return pointer to buffer */
+  return buffer; /* return pointer to buffer */
 }
 
 #endif /* DONE */
diff --git a/src/tool_paramhlp.h b/src/tool_paramhlp.h
index 192d242d18..af40f10591 100644
--- a/src/tool_paramhlp.h
+++ b/src/tool_paramhlp.h
@@ -44,7 +44,7 @@ ParameterError str2unum(long *val, const char *str);
 ParameterError oct2nummax(long *val, const char *str, long max);
 ParameterError str2unummax(long *val, const char *str, long max);
 ParameterError secs2ms(long *val, const char *str);
-ParameterError proto2num(const char * const *val, char **obuf,
+ParameterError proto2num(const char * const *val, char **ostr,
                          const char *str);
 ParameterError check_protocol(const char *str);
 ParameterError str2offset(curl_off_t *val, const char *str);
diff --git a/tests/libtest/first.h b/tests/libtest/first.h
index 425566ba14..4260882723 100644
--- a/tests/libtest/first.h
+++ b/tests/libtest/first.h
@@ -82,7 +82,7 @@ int cgetopt(int argc, const char * const argv[], const char *optstring);
 extern int select_wrapper(int nfds, fd_set *rd, fd_set *wr, fd_set *exc,
                           struct timeval *tv);
 
-extern char *hexdump(const unsigned char *buffer, size_t len);
+extern char *hexdump(const unsigned char *buf, size_t len);
 
 #ifndef CURL_DISABLE_WEBSOCKETS
 CURLcode ws_send_ping(CURL *curl, const char *send_payload);