C/C++ 静态库动态库实践

Source File

List:

• mylib.c
• mylib.h
• test.c

1. mkdir library and cd library
2. mkdir lib include
3. vim include/mylib.h

#ifndef __MYLIB_H__
#define __MYLIB_H__
int qpow(int, int);
#endif /* __MYLIB_H__ */

4. vim mylib.c

/******************************************************************************
 * File:             mylib.c
 *
 * Author:           Gsharp
 * Created:          05/15/21
 * Description:      library mylib implements
 *****************************************************************************/

#include "mylib.h"

int qpow(int a, int n) {
  int res = 1;
  if (a < 0 || n < 0) {
    return -1;
  }
  while (n) {
    if (n & 1) res *= a;
    a *= a;
    n >>= 1;
  }
  return res;
}

6. wirte a test

#include <stdio.h>

#include "mylib.h"
int main(int argc, char *argv[]) {
  printf("%d ^ %d = %d", 3, 10, qpow(3, 10));
  return 0;
}

Static Library

Build

1. gcc -g -Wall -Werror -fPIC -c lib/mylib.c -I./include you will get mylib.o
2. ar rcs lib/libmylib.a mylib.o

Usage

• gcc test.c -static -I include/ -L lib/ -lmylib -o test

Dynamic Library

Build

gcc -g -Wall -Werror -Wextra -fPIC -shared -pedantic mylib.c -o lib/libmylib.so

Usage

• export LD_LIBRARY_PATH=./lib:$LD_LIBRARY_PATH
• gcc test.c -I inlude/ -L lib/ -lmylib -o test