p4-9.c

SUN Solaris8平台下进程间通信

#include <unistd.h>
#include <fcntl.h> 
#include <errno.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
    /* 检查参数合法否 */    
    if (argc != 2){
        printf("usage: a.out <filename>\n");
        exit(1);
    }     
    /* 检查实际用户是否有读权限 */
    if (access(argv[1],R_OK) < 0){              
        printf("access error for %s. ",argv[1]);
        if (errno == EACCES)
            printf("you are not the owner of this file!\n");
    }
    else
        printf("read access OK\n");
    /* 无论是否有实际用户读权限，仍尝试打开该文件 */
    if (open(argv[1], O_RDONLY) < 0)
        printf("open error for %s\n",argv[1]);
    else
        printf("open for reading OK\n");
    exit(0);  
}