CheckPrototypeDefinition

This module provides a command to check if a C function has the expected prototype.

Load this module in a CMake project with:

include(CheckPrototypeDefinition)

Commands

This module provides the following command:

check_prototype_definition

Checks if a C function has the expected prototype:

check_prototype_definition(<function> <prototype> <return> <headers> <variable>)

<function>

The name of the function whose prototype is being checked.

<prototype>

The expected prototype of the function, provided as a string.

<return>

The return value of the function. This will be used as a return value in the function definition body of the generated test program to verify that the function's return type matches the expected type.

<headers>

A semicolon-separated list of header file names required for checking the function prototype.

<variable>

The name of the variable to store the check result. This variable will be created as an internal cache variable.

This command generates a test program and verifies that it builds without errors. The generated test program includes specified <headers>, defines a function with given literal <prototype> and <return> value and then uses the specified <function>. The simplified test program can be illustrated as:

#include <headers>
// ...
<prototype> { return <return>; }
int main(...) { ...<function>()... }

Variables Affecting the Check

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

CMAKE_REQUIRED_FLAGS

A space-separated string of additional flags to pass to the compiler. A semicolon-separated list will not work. The contents of CMAKE_<LANG>_FLAGS and its associated configuration-specific CMAKE_<LANG>_FLAGS_<CONFIG> variables are automatically prepended to the compiler command before the contents of this variable.

CMAKE_REQUIRED_DEFINITIONS

A semicolon-separated list of compiler definitions, each of the form -DFOO or -DFOO=bar. A definition for the name specified by the result variable argument of the check command is also added automatically.

CMAKE_REQUIRED_INCLUDES

A semicolon-separated 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

Added in version 3.14.

A semicolon-separated list of options to add to the link command (see try_compile() for further details).

CMAKE_REQUIRED_LIBRARIES

A semicolon-separated list of libraries to add to the link command. These can be the names of system libraries, or they can be Imported Targets (see try_compile() for further details).

CMAKE_REQUIRED_LINK_DIRECTORIES

Added in version 3.31.

A semicolon-separated list of library search paths to pass to the linker (see try_compile() for further details).

CMAKE_REQUIRED_QUIET

Added in version 3.1.

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

Examples

Checking if the getpwent_r() function on Solaris/illumos systems has the expected prototype:

include(CheckPrototypeDefinition)

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