CMake How to use

CMake is a cross-platform installation (compilation) tool that can be used to describe the installation of all platforms (the compilation process) with simple statements. He is able to output a variety of Makefile or project files that can test the C + + features supported by the compiler, similar to the Automake under UNIX.

CMake How to use

All of the CMake statements are written in a file called: CMakeLists.txt. When the CMakeLists.txt file is determined, the associated variable value can be configured with the Ccmake command. This command must point to the directory where the CMakeLists.txt is located. After the configuration is complete, apply the CMake command to generate the appropriate makefile (under the UNIX like system) or the project file (specified with the appropriate programming tools under window).

Its basic operating procedures are:

1. $> Ccmake Directory

2. $> CMake Directory

3. $> make

Where directory is the directory where CMakeList.txt resides;

• The first statement is used to configure the compilation options, such as the Vtk_dir directory, the general step does not need to configure, directly execute the second statement, but when there is an error, it is necessary to consider the configuration, this step is really useful;
• The second command is used to generate makefile files based on CMakeLists.txt;
• The third command is used to execute the makefile file, compile the program, and generate the executable file;

CMake implementation is so simple, the difficulty lies in how to write CMakeLists.txt files, the following example of a simple introduction to CMakeLists.txt writing, see the following CMakeLists.txt

1. #project Name

2. PROJECT (Test_math)

3. #head file path

4. Include_directories (

5. Include

6. )

7. #source Directory

8. Aux_source_directory (src Dir_srcs)

9. #set environment variable

10. SET (Test_math

11. ${DIR_SRCS}

12. )

13. #set extern Libraries

14. SET (LIBRARIES

15. Libm.so

16. )

17. #add executable file

18. Add_executable (.. /bin/bin ${test_math})

19. #add link Library

20. Target_link_libraries (.. /bin/bin ${libraries})

or use the following CMakeLists.txt

1. #project Name

2. PROJECT (Test_math)

3. #head file path

4. Include_directories (

5. Include

6. )

7. #source Directory

8. Aux_source_directory (src Dir_srcs)

9. #set environment variable

10. SET (Test_math

11. ${DIR_SRCS}

12. )

13. #add executable file

14. Add_executable (.. /bin/bin ${test_math})

15. #add link Library

16. Target_link_libraries (.. /bin/bin m)

This is the CMakeLists.txt of a program that tests mathematical functions, followed by "#" as the contents of a comment, and CMake commands are all uppercase

Line 2nd specifies that the generated project is named Test_math

Line 4th specifies that the header file directory is include

Line 8th specifies that the source file directory is SRC and assigns it to the environment variable Dir_srcs

Line 10th sets the value of the environment variable Test_math to the value of the environment variable DIR_SRCS, which is used here to show how environment variables are assigned to an environment variable

The 14th line is to assign the math library to the environment variable libraries, which, of course, can be used without this environment variable, and directly using the library name later

Line 18th is used to specify the build file to compile all the files in the environment variable Test_math directory. Executable file bin in the/bin directory

Line 20th specifies: /bin/bin the link library at execution time is the value of the environment variable libraries-libm.so

The source file is given below
/SRC/MAIN.C:

1. #include <stdio.h>

2. #include ". /include/a.h "

3. int main ()

4. {

5. Double b=25.0;

6. Double a=0.0;

7. A=get_sqrt (b);

9. printf ("A is%LF, B is%lf\n", A, A, a, a);

10. return 0;

11. }

/src/a.c

1. #include ". /include/a.h "

2. Double get_sqrt (double var1)

3. {

4. return sqrt (VAR1);

5. }

/include/a.h

#ifndef A_file_header_inc

2. #define A_file_header_inc

3. #include <math.h>

5. Double get_sqrt (double var1);

7. #endif

Place the CMakeLists.txt in the current directory and execute the CMakeLists.txt

1. $> CMake.

2. $> make

You can build the executable file in the bin file under directory/bin, so run to see if it works the way you want it to.

CMake use Method (RPM)