Require CMake 3.18 (2020-07-15) or newer, up from 3.7 (2016-11-11)
prior to this patch.
This requirement also applies to the distributed `curl-config.cmake`.
To allow dropping compatibility code maintained for old versions, and to
use features which were unpractical in separate code paths. Also to make
testing, documentation and development easier, CI builds faster due to
CMake performance improvements over time. (e.g. integration tests on
macOS run 8x faster (10 minutes is now under 1.5m) in CI, 2.5x faster on
Windows.)
CMake offers pre-built binaries for major platforms. They work without
an install step, just by unpacking and pointing the cmake command to
them. Making upgrades easy in many cases:
https://cmake.org/download/https://cmake.org/files/https://github.com/Kitware/CMake/releases
CMake 3.18 brings these feature as generally available when building or
consuming curl/libcurl:
LTO support, improved performance, `pkg-config` and interface target
support, `OBJECT` target (for faster libcurl builds), modern invocation
with `-S`/`-B` options, better support for custom linker options,
FetchContent, `GnuTLS::GnuTLS` target, `--verbose` and `--install`
options, `CMAKE_GENERATOR` env, last but not least unity mode and Ninja
generator.
For maximum build speed, use:
`-DCMAKE_UNITY_BUILD=ON -DCURL_DROP_UNUSED=ON`
As for deprecations, C++11 is required to build CMake itself, which may
be a limit on some platforms. autotools continues to cover them.
Follow-up to 9bcdfb3809#20408
Follow-up to a7c974e038#19902
Follow-up to dfbe035c8b#10161
Discussion: https://github.com/curl/curl/discussions/18704Closes#20407
Rework the way curl's custom Find modules advertise their properties.
Before this patch, Find modules returned detected dependency properties
(header dirs, libs, libdirs, C flags, etc.) via global variables. curl's
main `CMakeLists.txt` copied their values into global lists, which it
later applied to targets. This solution worked internally, but it was
unsuited for the public, distributed `CURLConfig.cmake` and publishing
curl's Find modules with it, due to polluting the namespace of consumer
projects. It's also impractical to apply the many individual variables
to every targets depending on libcurl.
To allow using Find modules in consumer projects, this patch makes them
define as imported interface targets, named `CURL::<dependency>`. Then
store dependency information as target properties. It avoids namespace
pollution and makes the dependency information apply automatically
to all targets using `CURL::libcurl_static`.
Find modules continue to return `*_FOUND` and `*_VERSION` variables.
For dependencies detected via `pkg-config`, CMake 3.16+ is recommended.
Older CMake versions have a varying degree of support for
propagating/handling library directories. This may cause issues in envs
where dependencies reside in non-system locations and detected via
`pkg-config` (e.g. macOS + Homebrew). Use `CURL_USE_PKGCONFIG=OFF`
to fix these issues. Or upgrade to newer CMake, or link libcurl
dynamically.
Also:
- re-enable `pkg-config` for old cmake `find_library()` integration
tests.
- make `curlinfo` build after these changes.
- distribute local Find modules.
- export the raw list of lib dependencies via `CURL_LIBRARIES_PRIVATE`.
- `CURLconfig.cmake`: use curl's Find modules to detect dependencies in
the consumer env.
- add custom property to target property debug function.
- the curl build process no longer modifies `CMAKE_C_FLAGS`.
Follow-up to e86542038d#17047
Ref: #14930
Ref: https://github.com/libssh2/libssh2/pull/1535
Ref: https://github.com/libssh2/libssh2/pull/1571
Ref: https://github.com/libssh2/libssh2/pull/1581
Ref: https://github.com/libssh2/libssh2/pull/1623Closes#16973
To not have to guess. Also to sync with autotools, which already uses
this wording.
Also:
- replace the stray term 'folder' with 'directory' for consistency.
- store help text in a temp variable to avoid overly long strings
(mandatory in CMake <4.2.0 and can't be trivially split), also
to avoid repeating this string 4 times.
Ref: https://cmake.org/cmake/help/v4.2/command/set.htmlCloses#19169
For Find modules where `<Modulename>` is not fully uppercase.
`<Modulename>` is case-exact name used in the Find modules filename:
`CMake/Find<Moduleame>.cmake`.
`find_package_handle_standard_args()` sets both `<MODULENAME>_FOUND` and
`<Modulename>_FOUND` when detecting the dependency. Some CMake code
relies on this and 3rd-party code may rely on it too. Make sure to set
the latter variant when detecting the dependency via `pkg-config`, where
we don't call `find_package_handle_standard_args()`.
CMake sets these variable to `TRUE` (not `ON` or `1`). Replicate this
for compatibility.
Closes#16153
Make the Find modules set and return their respective `pkg-config`
module name(s) to the CMake build process, which then adds those
to the `Requires:` list.
Before this patch, `pkg-config` module names were maintainted in two
separate places. After this patch, they are maintained in the Find
modules for dependencies that have one (most do).
Re-align existing modules with this change: msh3, mbedtls, rustls.
These modules return their `pkg-config` module name only when
detected via `pkg-config`.
Follow-up to d511ec8b0a#15573Closes#15800
Extend `INSTALL-CMAKE` document with the list of available options,
a short description and default values.
The list may not be 100% complete.
There are no component boundaries in CMake, so the line is blurry
between curl options, CMake options, CMake Find modules options.
I included certain CMake options that seemed useful, and/or have
dedicated use withing curl's CMake source. But, all CMake built-in
options are usable, as documented upstream in CMake.
The naming of the options has a heritage and the inconsistencies with
it, including a lack of clear namespace. This may be subject to future
updates, also after figuring out which name has special meaning within
CMake and/or CMake projects out of unwritten convention or something
more tangible.
CMake allows to initialize any internal variable via `-D`. This may be
useful to pre-initialize/override feature check results. The list
doesn't contain these, and they remain officially undocumented.
Also:
- make adjustments to keep the spellchecker happy.
- retrofit description changes to the cmake sources.
- stop documenting deprecated `Find*` variables.
Reported-by: Daniel Stenberg
Fixes https://github.com/curl/curl/discussions/14885Closes#15388
In Find modules with native pkg-config detection (libgsasl, libidn2,
libssh, libuv, nettle) use the C compiler flags returned by pkg-config.
Also use the library paths, and return the pathless library names.
Also:
- add these library paths to `libcurl.pc`/`curl-config`.
- fix libgsasl detection to use the detected header directory.
FindGSS already did this before this patch.
Fixes#14641Closes#14652
- fix BearSSL warning about name mismatch.
- fix Nettle Find module not found on Linux.
- tidy-up: drop quotes from a package name.
Package names must match case-sensitively to work on all platforms:
- `find_package(<NAME> ...)` in `CMakeLists.txt`.
- `CMake/Find<NAME>.cmake` filenames.
- `find_package_handle_standard_args(<NAME> ...` in Find modules.
- `message(STATUS "Found <NAME> ...` in Find modules.
(to match the message shown by `find_package_handle_standard_args()`)
Closes#14599
If either `NETTLE_INCLUDE_DIR` or `NETTLE_LIBRARY` is set to customize
the `nettle` dependency, skip `pkg-config` and use the CMake-native
detection to honor these custom settings.
Closes#14584
- add `NAMES` where missing.
- document input variables (including deprecated ones.)
- comment cleanups.
- FindWolfSSL: drop stray `QUIET` from `pkg_check_modules()`.
(`QUIET` may be re-added for all modules in the future.)
Closes#14579
- use the same pattern across all Find modules:
- verify if the version header exists before reading it.
- use a single regex per lookup.
- sync regexes between Find modules.
- use generic temporary variable names.
- improve readability.
- make it simpler to transition to new CMake syntax in the future:
```cmake
file(STRINGS "${CARES_INCLUDE_DIR}/ares_version.h" _version_str REGEX "<...>")
unset(_version_str)
set(CARES_VERSION "${CMAKE_MATCH_1}")
```
Ref: https://cmake.org/cmake/help/latest/policy/CMP0159.html#policy:CMP0159
- fix zstd version detection to be CMake 3.7 compatible.
Required 3.9 before this patch, for the `CMAKE_MATCH_<n>` feature.
Follow-up to c5d506e9bb#12200
Follow-up to 4e2f3641f8#14548Closes#14572
Prefer `pkg_check_modules()` over `pkg_search_module()`.
`pkg_check_modules()` logs a line when there is a hit, and also warnings
if a sub-dependency is missing. In `QUIET` mode, both are silent.
The extra info is useful to see if a detection happened via
`pkg-config`.
Keep `pkg_search_module()` in `FindGSS`. We pass two dependencies
there and we want to keep stopping on the first one.
Partially reverts c2889a7b41#14388Closes#14573
Add option to control whether to use `pkg-config` to detect
dependencies. Curl's CMake uses `pkg-config` by default for all targets
except for MSVC without vcpkg.
With the CMake option `-DCURL_USE_PKGCONFIG=ON` you can override it to
use `pkg-config` always.
If `pkg-config` is causing issues, e.g. in cross-builds or other cases,
`-DCURL_USE_PKGCONFIG=OFF` disables all use of `pkg-config`.
Also add it to `curl-config.cmake`. Not yet used, but will be once curl
starts referencing any curl-specific `Find*` module from this public
script.
Follow-up to 9dfdc6ff42#14483Closes#14504
Before this patch, `pkg-config` was used for `UNIX` builds only (with
a few exceptions like wolfSSL, libssh, gsasl, libuv). This patch extends
`pkg-config` use to all envs except: `MSVC` without vcpkg. Meaning MSVC
with vcpkg will now use it. Also mingw on Windows.
Also apply the new condition to options where `pkg-config` was used
unconditionally (= for all targets). These are:
`-DCURL_USE_WOLFSSL=ON`, `-DCURL_USE_LIBSSH=ON`,
`-DCURL_USE_GSASL=ON` and `-DCURL_USE_LIBUV=ON`
This patch may still cause regressions for cross-builds (e.g. mingw
cross-build from Unix) and potentially other cases. If that happens, we
recommend using some of these methods to explicitly disable `pkg-config`
when using CMake:
- CMake option: `-DPKG_CONFIG_EXECUTABLE=`
(or `-DPKG_CONFIG_EXECUTABLE=nonexistent` or similar)
This is similar to the (curl-specific) `PKG_CONFIG` env for autotools.
- export env: `PKG_CONFIG_LIBDIR=`
(or `PKG_CONFIG_PATH`, `PKG_CONFIG_SYSROOT_DIR`,
or the CMake-specific `PKG_CONFIG`)
We may improve control over this in a future patch, also allowing opting
in MSVC (without vcpkg).
Ref: #14405
Ref: #14408
Ref: #14140Closes#14483
- quote string literals.
In the hope it improves syntax-highlighting and readability.
- use lowercase, underscore-prefixed local var names.
As a hint for scope, to help readability.
- prefer `pkg_search_module` (over `pkg_check_modules`).
They are the same, but `pkg_search_module` stops searching
at the first hit.
- more `IN LISTS` in `foreach()`.
- OtherTests.cmake: clear `CMAKE_EXTRA_INCLUDE_FILES` after use.
- add `PROJECT_LABEL` for http/client and unit test targets.
- sync `Find*` module comments and formatting.
- drop a few local variables.
- drop bogus `CARES_LIBRARIES` from comment.
- unquote numeric literal.
Follow-up to acbc6b703f#14197Closes#14388
- tidy-up comments.
- use lowercase, underscore prefixed names for internal variables.
- use `IN LISTS` and `IN ITEMS` in `foreach()` loops.
- rename variable name `OUTPUT` to a more distinctive one.
- tidy-up `STREQUAL` syntax.
- delete commented code.
- indent/whitespace.
Closes#14197
The oldest cmake supported by curl is v3.7.0, which already has such
guard (using `PKG_CONFIG_EXECUTABLE`) inside `pkg_check_modules()`. The
advantage of leaving that guard to CMake is that it will define/reset
all output variables, while the manual guard doesn't do this and also
leaves for example `NETTLE_FOUND` undefined.
Delete the single use of this guard from the recently added `nettle`
detection, where I included it by accident. Then possibly re-introduce
it universally if we find it useful after more evaluation.
Follow-up to 669ce42275#14285Closes#14309
`nettle` is a direct dependency of curl, when building with GnuTLS.
Add a new `Find` module to detect it.
Also:
- GHA/macos: drop `nettle` hack no longer necessary.
- add `nettle` to `libcurl.pc`.
- also add `nettle` to `libcurl.pc` in autotools builds.
Follow-up to 781242ffa4#11967Closes#14285
