curl-curl/docs/libcurl/curl_slist_append.md

c	SPDX-License-Identifier	Title	Section	Source	See-also	Protocol	Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.	curl	curl_slist_append	3	libcurl	curl_slist_free_all (3)	All	7.1

NAME

curl_slist_append - add a string to an slist

SYNOPSIS

#include <curl/curl.h>

struct curl_slist *curl_slist_append(struct curl_slist *list,
                                     const char *string);

DESCRIPTION

curl_slist_append(3) appends a string to a linked list of strings. The existing list should be passed as the first argument and the new list is returned from this function. Pass in NULL in the list argument to create a new list. The specified string has been appended when this function returns. curl_slist_append(3) copies the string. The string argument must be a valid string pointer and cannot be NULL.

The list should be freed (after usage) with curl_slist_free_all(3). Its nodes and pointed content may not be altered outside this function.

%PROTOCOLS%

EXAMPLE

int main(void)
{
  CURL *handle = curl_easy_init();
  struct curl_slist *slist = NULL;
  struct curl_slist *temp = NULL;

  slist = curl_slist_append(slist, "pragma:");

  if(!slist)
    return -1;

  temp = curl_slist_append(slist, "Accept:");

  if(!temp) {
    curl_slist_free_all(slist);
    return -1;
  }

  slist = temp;

  curl_easy_setopt(handle, CURLOPT_HTTPHEADER, slist);

  curl_easy_perform(handle);

  curl_slist_free_all(slist); /* free the list again */
}

%AVAILABILITY%

RETURN VALUE

A null pointer is returned if anything went wrong, otherwise the new list pointer is returned. To avoid overwriting an existing non-empty list on failure, the new list should be returned to a temporary variable which can be tested for NULL before updating the original list pointer.