# CheckIncludeFiles

Provides a macro to check if a list of one or more header files can be included together.

`CHECK_INCLUDE_FILES`

      CHECK_INCLUDE_FILES("<includes>" <variable> [LANGUAGE <language>])

  Check if the given `<includes>` list may be included together in a source file and store the result in an internal cache entry named `<variable>`. Specify the `<includes>` argument as a ;-list of header file names.

  If `LANGUAGE` is set, the specified compiler will be used to perform the check. Acceptable values are `C` and `CXX`. If not set, the C compiler will be used if enabled. If the C compiler is not enabled, the C++ compiler will be used if enabled.

The following variables may be set before calling this macro to modify the way the check is run:

`CMAKE_REQUIRED_FLAGS`

  string of compile command line flags.

`CMAKE_REQUIRED_DEFINITIONS`

  a ;-list of macros to define (-DFOO=bar).

`CMAKE_REQUIRED_INCLUDES`

  a ;-list of header search paths to pass to the compiler.

`CMAKE_REQUIRED_LINK_OPTIONS`

  New in version 3.14: a ;-list of options to add to the link command.

`CMAKE_REQUIRED_LIBRARIES`

  a ;-list of libraries to add to the link command. See policy `CMP0075`.

`CMAKE_REQUIRED_QUIET`

  New in version 3.1: execute quietly without messages.

See modules `CheckIncludeFile` and `CheckIncludeFileCXX` to check for a single header file in `C` or `CXX` languages.