Gcc shared object, gccshared

Gcc shared object, gccshared

An example of generating a dynamic link library *. so is introduced: first create a new 1 Head file test. h:

#include <stdio.h>void first();void second();void third();

Create three source files first. c/second. c/third. c:

First. c:

#include "test.h"void first() {    printf("this is first.\n");}

 

Second. c:

#include "test.h"void second() {    printf("this is second.\n");}

 

Third. c:

#include "test.h"void third() {    printf("this is third.\n");}

 

Then, generate the dynamic link library libtest. so: gcc first. c second. c third. c-fPIC-shared-o libtest. so
Note: 1.-fPIC indicates that the code location is independent for program sharing. 2.-shared means to generate a dynamic link library

Next, create a source code test. c that calls the Dynamic Link Library:

#include "test.h"void main(){    first();    second();    third();}

Generate the executable file: gcc test. c-L.-ltest-o test
Note:-L. indicates that the link library is in the current directory;-ltest indicates that the link library libtest. so is found based on implicit rules.

Execute./test to obtain the following results:

this is first.this is second.this is third.

If you don't get this result, you will be prompted ". /test: error while loading shared libraries: libtest. so: cannot open shared object file: No such file or directory ", then in/etc/ld. so. conf. create a test. conf configuration file, and write the access path of your dynamic link library in this file, such as/usr/local/demo/lib, depending on your own situation. After the configuration is completed, type sudo ldconfig to make the configuration take effect.

Over.

Ps:
You can also create a soft link, for example, ln-s/your_folder/* so/usr/lib.