# CheckLibraryExists

Check if the function exists.

`CHECK_LIBRARY_EXISTS`

      CHECK_LIBRARY_EXISTS(LIBRARY FUNCTION LOCATION VARIABLE)

      LIBRARY  - the name of the library you are looking for
      FUNCTION - the name of the function
      LOCATION - location where the library should be found
      VARIABLE - variable to store the result
                 Will be created as an internal cache variable.

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`

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

`CMAKE_REQUIRED_LINK_OPTIONS`

  New in version 3.14: list of options to pass to link command.

`CMAKE_REQUIRED_LIBRARIES`

  list of libraries to link.

`CMAKE_REQUIRED_QUIET`

  New in version 3.1: execute quietly without messages.