Unix 线程共享创建进程打开的文件资源（1）

执行环境：Linux ubuntu 4.4.0-31-generic #50-Ubuntu SMP Wed Jul 13 00:07:12 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

1. 测试代码 : a.c

 #include <fcntl.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <pthread.h>
 #include <string.h>

 pthread_t ntid;

 void * thr_fn(void * arg)
 {
    int * fp = (int *)arg;
    char * str = "Hello the world!\n";

    int len = write(*fp,str,strlen(str));
    if(len)
    {
     printf("Thread write a string to the file by the descriptor the createprocess created!\n");
    }

    close(*fp);
    return ((void *));
 }

 int main(void)
 {
     int err;
     int fd;

     fd = open("log.txt",O_CREAT|O_WRONLY);
     if(- == fd)
     {
     printf("Failed to open  file!\n");
     }

     err = pthread_create(&ntid,NULL,thr_fn,&fd);
     if(err != )
     {
     printf("can't create thread ,errno = %d\n",err);
     }
     sleep();
     return ;
 }

2. 如果系统没有相应的pthread库，执行：

sudo apt-get install glibc-doc

2 sudo apt-get install manpages-posix-dev

编译运行：

gcc a.c -lpthread