Provides a macro to check if a header file can be included in C.

CHECK_INCLUDE_FILE(<include> <variable> [<flags>])

Check if the given <include> file may be included in a C source file and store the result in an internal cache entry named <variable>. The optional third argument may be used to add compilation flags to the check (or use CMAKE_REQUIRED_FLAGS below).

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

string of compile command line flags
list of macros to define (-DFOO=bar)
list of include directories
execute quietly without messages

See the CheckIncludeFiles module to check for multiple headers at once. See the CheckIncludeFileCXX module to check for headers using the CXX language.