cmake Configure file Examble based on SDL2 control version

Example

If you have a cmake module . You can create a folder called in to store all config files.

For example,you have a project called FOO, you can create a FOO_config.h.in file like:

//===================================================================================
//  CMake configuration file, based on SDL 2 version header
// ===================================================================================

#pragma once

#include <string>
#include <sstream>

namespace yournamespace
{
  /**
 *  \brief Information the version of FOO_PROJECT in use.
 *
 *  Represents the library's version as three levels: major revision
 *  (increments with massive changes, additions, and enhancements),
 *  minor revision (increments with backwards-compatible changes to the
 *  major revision), and patchlevel (increments with fixes to the minor
 *  revision).
 *
 *  \sa FOO_VERSION
 *  \sa FOO_GetVersion
 */
typedef struct FOO_version
{
    int major;        /**< major version */
    int minor;        /**< minor version */
    int patch;        /**< update version */
} FOO_version;

/* Printable format: "%d.%d.%d", MAJOR, MINOR, PATCHLEVEL
*/
#define FOO_MAJOR_VERSION   0
#define FOO_MINOR_VERSION   1
#define FOO_PATCHLEVEL      0

/**
 *  \brief Macro to determine FOO version program was compiled against.
 *
 *  This macro fills in a FOO_version structure with the version of the
 *  library you compiled against. This is determined by what header the
 *  compiler uses. Note that if you dynamically linked the library, you might
 *  have a slightly newer or older version at runtime. That version can be
 *  determined with GUCpp_GetVersion(), which, unlike GUCpp_VERSION(),
 *  is not a macro.
 *
 *  \param x A pointer to a FOO_version struct to initialize.
 *
 *  \sa FOO_version
 *  \sa FOO_GetVersion
 */
#define FOO_VERSION(x)                          \
{                                   \
    (x)->major = FOO_MAJOR_VERSION;                 \
    (x)->minor = FOO_MINOR_VERSION;                 \
    (x)->patch = FOO_PATCHLEVEL;                    \
}

/**
 *  This macro turns the version numbers into a numeric value:
 *  \verbatim
    (1,2,3) -> (1203)
    \endverbatim
 *
 *  This assumes that there will never be more than 100 patchlevels.
 */
#define FOO_VERSIONNUM(X, Y, Z)                     \
    ((X)*1000 + (Y)*100 + (Z))

/**
 *  This is the version number macro for the current GUCpp version.
 */
#define FOO_COMPILEDVERSION \
    FOO_VERSIONNUM(FOO_MAJOR_VERSION, FOO_MINOR_VERSION, FOO_PATCHLEVEL)

/**
 *  This macro will evaluate to true if compiled with FOO at least X.Y.Z.
 */
#define FOO_VERSION_ATLEAST(X, Y, Z) \
    (FOO_COMPILEDVERSION >= FOO_VERSIONNUM(X, Y, Z))

}

// Paths
#cmakedefine FOO_PATH_MAIN "@FOO_PATH_MAIN@"

This file will create a FOO_config.h in the install path, with a variable defined in c FOO_PATH_MAIN from cmake variable. To generate it you need to include in file in your CMakeLists.txt,like this (set paths and variables):

MESSAGE("Configuring FOO_config.h ...")
configure_file("${CMAKE_CURRENT_SOURCE_DIR}/common/in/FOO_config.h.in"
"${FOO_PATH_INSTALL}/common/include/FOO_config.h" )

That file will contain the data from template, and variable with your real path, for example:

// Paths
#define FOO_PATH_MAIN "/home/YOUR_USER/Respositories/git/foo_project"