Category:CMake

CMake
This programming language may be used to instruct a computer to perform a task.

Official website

Execution method:	Interpreted
Lang tag(s):	cmake

Listed below are all of the tasks on Rosetta Code which have been solved using CMake.

CMake is a cross-platform make system, for compiling C, C++ or Fortran programs. CMake uses a configuration file (CMakeLists.txt) to run configure tests, find libraries, create targets, and generate a build system for Unix make or another build tool. This configuration file runs commands in CMake's own scripting language.

In process script mode (cmake -P myscript.cmake), CMake runs the script but cannot create a project or any targets.

Example

This example builds a small C program after checking if #include <sys/time.h> provides clock_gettime() or gettimeofday().

CMakeLists.txt

<lang cmake># CMakeLists.txt cmake_minimum_required(VERSION 2.6) project(simpletime C) # This project will use the C compiler.

1. Check if this system has clock_gettime() or gettimeofday(),
2. then generate config.h with the results.

include(CheckSymbolExists) check_symbol_exists(clock_gettime sys/time.h HAVE_CLOCK_GETTIME) check_symbol_exists(gettimeofday sys/time.h HAVE_GETTIMEOFDAY) configure_file(config.h.in config.h)

1. Allow C to #include <config.h>, if doing out-of-source build.

include_directories(${CMAKE_CURRENT_BINARY_DIR})

1. This target will make an executable from the given
2. source files and any included header files.

add_executable(simpletime simpletime.c)

1. The install target will install the executable
2. to ${CMAKE_INSTALL_PREFIX}/bin.

install(TARGETS simpletime DESTINATION bin)</lang>

config.h.in

<lang c>/* config.h, generated from config.h.in by CMake ${CMAKE_VERSION} */

1. cmakedefine HAVE_CLOCK_GETTIME
2. cmakedefine HAVE_GETTIMEOFDAY</lang>

simpletime.c

<lang c>/* simpletime.c */

1. include "config.h"

1. if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_GETTIMEOFDAY)
2. include <sys/time.h>
3. endif
4. include <stdio.h>
5. include <time.h>

/*

* Simply print the current time.
*/

int main() {

1. if defined(HAVE_CLOCK_GETTIME)

struct timespec ts; clock_gettime(CLOCK_REALTIME, &ts); printf("The time is %s" "and %ld nanoseconds.\n", ctime(&ts.tv_sec), ts.tv_nsec);

1. elif defined(HAVE_GETTIMEOFDAY)

struct timeval tv; gettimeofday(&tv, NULL); printf("The time is %s" "and %ld microseconds.\n", ctime(&tv.tv_sec), tv.tv_usec);

1. else

time_t sec; sec = time(NULL); printf("The time is %s", ctime(&sec));

1. endif

return 0; }</lang>

If the three files CMakeLists.txt, config.h.in and simpletime.c are in .., then cmake .. configures the project.

$ cmake ..
-- The C compiler identification is GNU
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Looking for clock_gettime
-- Looking for clock_gettime - found
-- Looking for gettimeofday
-- Looking for gettimeofday - found
-- Configuring done
-- Generating done
-- Build files have been written to: /home/kernigh/field/rc/simpletime/work
$ make
Scanning dependencies of target simpletime
[100%] Building C object CMakeFiles/simpletime.dir/simpletime.c.o
Linking C executable simpletime
[100%] Built target simpletime
$ ./simpletime
The time is Wed Sep  7 17:10:55 2011
and 993848603 nanoseconds.