# CheckPrototypeDefinition

Check if the prototype we expect is correct.

check_prototype_definition

      check_prototype_definition(FUNCTION PROTOTYPE RETURN HEADER VARIABLE)

      FUNCTION - The name of the function (used to check if prototype exists)
      PROTOTYPE- The prototype to check.
      RETURN - The return value of the function.
      HEADER - The header files required.
      VARIABLE - The variable to store the result.
                 Will be created as an internal cache variable.

  Example:

      check_prototype_definition(getpwent_r
       "struct passwd *getpwent_r(struct passwd *src, char *buf, int buflen)"
       "NULL"
       "unistd.h;pwd.h"
       SOLARIS_GETPWENT_R)

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

> `CMAKE_REQUIRED_FLAGS`

>   String of additional flags to pass to the compiler. The string must be space-delimited--a ;-list will not work. The contents of `CMAKE_<LANG>_FLAGS` and its associated configuration-specific variable are automatically added to the compiler command before the contents of `CMAKE_REQUIRED_FLAGS`.

> `CMAKE_REQUIRED_DEFINITIONS`

>   A ;-list of compiler definitions of the form `-DFOO` or `-DFOO=bar`. A definition for the name specified by `<resultVar>` will also be added automatically.

> `CMAKE_REQUIRED_INCLUDES`

>   A ;-list of header search paths to pass to the compiler. These will be the only header search paths used--the contents of the `INCLUDE_DIRECTORIES` directory property will be ignored.

> `CMAKE_REQUIRED_LINK_OPTIONS`

>   New in version 3.14.

>   A ;-list of options to add to the link command (see `try_compile()` for further details).

> `CMAKE_REQUIRED_LIBRARIES`

>   A ;-list of libraries to add to the link command. These can be the name of system libraries or they can be Imported Targets (see `try_compile()` for further details).

> `CMAKE_REQUIRED_QUIET`

>   New in version 3.1.

>   If this variable evaluates to a boolean true value, all status messages associated with the check will be suppressed.