《C编译原理》共享库的动态加载和静态加载

一、共享库的编译

1.共享库源码

lib.h

int function(void);

lib.c

#include "lib.h"
#include <stdio.h>
int function(void){
  printf("TK--------->>>>this is sharelib function\n");
}

2.编译

gcc -shared -fPIC -o libfunc.so lib.c

生成libfunc.so

二、共享库的静态装载

1.测试用例

main.c

#include <stdio.h>
#include "lib.h"
int main(){
  int a = function();
}

2.编译

gcc -o main main.c -L. -lfunc

3.添加环境变量

vi /home/tankai/.bashrc

export LD_LIBRARY_PATH+=:/home/lianxi/share/static

即时生效：

source /home/tankai/.bashrc

三、共享库的动态装载

1.测试用例

main.c

#include <stdio.h>
#include <dlfcn.h> 

#define PATH "../static/libfunc.so"
void *handle = NULL;
int (*test) (void);

int main(){
 handle = dlopen(PATH, RTLD_NOW|RTLD_GLOBAL);
  if(handle == NULL){
    printf("dlopen:%s\n",dlerror);
  }
  dlerror();
  test = (int(*)(int))dlsym(handle,"function");
  if(test == NULL){
    printf("dlsym:%s\n",dlerror());
    dlclose(handle);
  } 
  int a = test();
  dlclose(handle);
}

2.编译

gcc -o main main.c -L. -ldl