studyuid.c

LINUX C编程实战这本书附带光盘的原代码

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

extern int errno;

int main()
{
	int fd;

	printf("uid study: \n");
	printf("Process's uid = %d,euid = %d\n",getuid(),geteuid());
	
	// strerror函数获取指定错误码的提示信息
	if((fd = open("test.c",O_RDWR)) == -1) {
        	printf("Open failure,errno is %d :%s \n",errno, strerror(errno) );
	        exit(1);
    	}
    	else {
        	printf("Open successfully!\n");
	}
	
	close(fd);
    	exit(0);
}