Static library and dynamic library construction and use

1. An instance of static library and dynamic library construction (and uploaded to the system, the paths are: /usr/lib and /usr/unclude/hello)

1) Create a build folder (empty) and CMakeLists.txt in an empty project, the specific contents are as follows:

①CMakeLists.txt

PROJECT(HELLOLIB)
ADD_SUBDIRECTORY(lib)

2) Build lib folder in empty project

3) Add hello.c, hello.h and CMakeLists.txt to the lib folder, the details are as follows:

①hello.c

#include "hello.h"
void HelloFunc()
{
    printf("Hello World\n");
}

②hello.h

#ifndef HELLO_H
#define HELLO_H
#include <stdio.h>
void HelloFunc();
#endif

③CMakeLists.txt

SET(LIBHELLO_SRC hello.c)
ADD_LIBRARY(hello SHARED ${LIBHELLO_SRC})
ADD_LIBRARY(hello_static STATIC ${LIBHELLO_SRC})
SET_TARGET_PROPERTIES(hello_static PROPERTIES OUTPUT_NAME "hello")
GET_TARGET_PROPERTY(OUTPUT_VALUE hello_static OUTPUT_NAME)
MESSAGE(STATUS  "This is the hello_static OUTPUT_NAME:" ${OUTPUT_VALUE})
SET_TARGET_PROPERTIES(hello PROPERTIES CLEAN_DIRECT_OUTPUT 1)
SET_TARGET_PROPERTIES(hello_static PROPERTIES CLEAN_DIRECT_OUTPUT 1)

INSTALL(TARGETS hello hello_static
LIBRARY DESTINATION lib
ARCHIVE DESTINATION lib)
INSTALL(FILES hello.h DESTINATION include/hello)

4) Enter the build path and enter in turn

①cmake -DCMAKE_INSTALL_PREFIX=/usr ..

②make

③make install

2. Use the library and header files uploaded by the installation

1) Create the src directory in the new project, write the source file main.c, and CMakeLists.txt

①main.c

#include <hello.h>
intmain()
{
    HelloFunc();
    return 0;
}

②CMakeLists.txt

INCLUDE_DIRECTORIES(/usr/include/hello)
TARGET_LINK_LIBRARIES(main hello)（或者TARGET_LINK_LIBRARIES(main libhello.so)）

2) Create a build directory under the project, enter build on the command line to build

①cmake ..

②make

3. Special environment variables CMAKE_INCLUDE_PATH and CMAKE_LIBRARY_PATH

1) Why do you need these two environment variables: In order to use our own dynamic libraries and header files more intelligently

2) How to use? (used on top of our previous example)

①Enter export CMAKE_INCLUDE_PATH=/usr/include/hello in the command line

② Modify CMakeLists.txt in src to:

ADD_EXECUTABLE(main main.c)
FIND_PATH(myHeader hello.h)
IF(myHeader)
INCLUDE_DIRECTORIES(${myHeader})
ENDIF(myHeader)
TARGET_LINK_LIBRARIES(main libhello.so)
LINK_DIRECTORIES(/home/wideking/cmakeDemo/libhello/bulid)
ADD_EXECUTABLE(main main.c)

③ Build

Static library and dynamic library construction and use

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