CheckSourceCompiles¶

在 3.19 版被加入.

This module provides a command that checks whether a source code can be built for a given language.

在 CMake 專案中使用以下命令載入該模組：

include(CheckSourceCompiles)

命令¶

該模組提供了以下命令：

check_source_compiles¶

Checks once whether the given source code can be built for the given language:

check_source_compiles(
  <lang>
  <code>
  <variable>
  [FAIL_REGEX <regexes>...]
  [SRC_EXT <extension>]
)

This command checks once that the source supplied in <code> can be compiled (and linked into an executable) for code language <lang>. The result of the check is stored in the internal cache variable specified by <variable>.

The arguments are:

<lang>: Language of the source code to check. Supported languages are: C, CXX, CUDA, Fortran, HIP, ISPC, OBJC, OBJCXX, and Swift.

在 3.21 版被加入: Support for HIP language.

在 3.26 版被加入: Support for Swift language.
<code>: The source code to check. This must be an entire program, as written in a file containing the body block. All symbols used in the source code are expected to be declared as usual in their corresponding headers.
<variable>: Variable name of an internal cache variable to store the result of the check, with boolean true for success and boolean false for failure.
FAIL_REGEX <regexes>...: If one or more regular expression patterns are provided, then failure is determined by checking if anything in the compiler output matches any of the specified regular expressions.
SRC_EXT <extension>: By default, the internal test source file used for the check will be given a file extension that matches the requested language (e.g., .c for C, .cxx for C++, .F90 for Fortran, etc.). This option can be used to override this with the .<extension> instead.

影響檢查的變數

可以在呼叫此命令之前設定以下變數，以修改檢查的執行方式：

CMAKE_REQUIRED_FLAGS: 一個以空格分隔的字串，包含要傳遞給編譯器的額外旗標。分號分隔列表將無法運作。CMAKE_<LANG>_FLAGS 及其關聯的特定組態 CMAKE_<LANG>_FLAGS_<CONFIG> 變數的內容會在該變數的內容之前自動預置到編譯器命令中。

CMAKE_REQUIRED_DEFINITIONS: 一個編譯器定義的分號分隔列表，每個定義的形式為 -DFOO 或 -DFOO=bar。由檢查命令的結果變數引數所指定的名稱的定義也會自動新增。

CMAKE_REQUIRED_INCLUDES: 一個要傳遞給編譯器的標頭搜尋路徑的分號分隔列表。這些將是唯一使用的標頭搜尋路徑；INCLUDE_DIRECTORIES 目錄屬性的內容將被忽略。

CMAKE_REQUIRED_LINK_OPTIONS: 在 3.14 版被加入.

一個要新增到連結命令的選項的分號分隔列表（詳情請參見 try_compile()）。

CMAKE_REQUIRED_LIBRARIES: 一個要新增到連結命令的程式庫的分號分隔列表。這些可以是系統程式庫的名稱，也可以是 Imported Targets`（詳情請參見 :command:`try_compile）。

CMAKE_REQUIRED_LINK_DIRECTORIES: 在 3.31 版被加入.

一個要傳遞給連結器的程式庫搜尋路徑的分號分隔列表（詳情請參見 try_compile()）。

CMAKE_REQUIRED_QUIET: 在 3.1 版被加入.

如果此變數的值為布林真值，則與檢查相關的所有狀態訊息都將被抑制。

CMAKE_TRY_COMPILE_TARGET_TYPE: Internally, the try_compile() command is used to perform the check, and this variable controls the type of target it creates. If this variable is set to EXECUTABLE (the default), the check compiles and links the test source code as an executable program. If set to STATIC_LIBRARY, the test source code is compiled but not linked.

範例¶

Example: Basic Usage¶

The following example demonstrates how to check whether the C++ compiler supports a specific language feature using this module. In this case, the check verifies if the compiler supports C++11 lambda expressions. The result is stored in the internal cache variable HAVE_CXX11_LAMBDAS:

include(CheckSourceCompiles)

check_source_compiles(CXX [[
  int main()
  {
    auto lambda = []() { return 42; };
    return lambda();
  }
]] HAVE_CXX11_LAMBDAS)

Example: Checking Code With Bracket Argument¶

The following example shows how to check whether the C compiler supports the noreturn attribute. Code is supplied using the 方括號引數 for easier embedded quotes handling:

include(CheckSourceCompiles)

check_source_compiles(C [[
  #if !__has_c_attribute(noreturn)
  #  error "No noreturn attribute"
  #endif
  int main(void) { return 0; }
]] HAVE_NORETURN)

Example: Performing a Check Without Linking¶

In the following example, this module is used to perform a compile-only check of Fortran source code, whether the compiler supports the pure procedure attribute:

include(CheckSourceCompiles)

block()
  set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY")

  check_source_compiles(
    Fortran
    "pure subroutine foo()
    end subroutine"
    HAVE_PURE
  )
endblock()

Example: Isolated Check¶

In the following example, this module is used in combination with the CMakePushCheckState module to modify required libraries when checking whether the PostgreSQL PGVerbosity enum contains PQERRORS_SQLSTATE (available as of PostgreSQL version 12):

include(CheckSourceCompiles)
include(CMakePushCheckState)

find_package(PostgreSQL)

if(TARGET PostgreSQL::PostgreSQL)
  cmake_push_check_state(RESET)
    set(CMAKE_REQUIRED_LIBRARIES PostgreSQL::PostgreSQL)

    check_source_compiles(C [[
      #include <libpq-fe.h>
      int main(void)
      {
        PGVerbosity e = PQERRORS_SQLSTATE;
        (void)e;
        return 0;
      }
    ]] HAVE_PQERRORS_SQLSTATE)
  cmake_pop_check_state()
endif()

另請參見¶

The CheckSourceRuns module to check whether the source code can be built and also run.