系统调用 5--write

#include <stdio.h>#include <sys/stat.h>#include <sys/types.h>#include <fcntl.h>#include <unistd.h>/**************************file:write.c*author:QG*time:2015-05-11*description:*************************/int main(){    char *in_file = "/home/project/test_program/test5/123.txt";    char *out_file = "./234.txt";    int a = 0;    int b = 0;    int c = 0;    a = open(in_file,O_RDONLY);    b = open(out_file,O_RDWR|O_CREAT,0755);    if(a < 0)    {        printf("open in_file fail!\n");    }    else if(a >= 0)    {        printf("open in_file OK!descriptor is %d \n",a);    }    if(b < 0)    {        printf("open out_file fail!\n");    }    else if(b > 0)    {        printf("open out_file OK!descriptor is %d \n",b);    }    c = write(b,in_file,9);    if(c < 0)    {        printf("write file fail!\n");    }    else if(c > 0)    {        printf("write file OK !write %d types!\n",c);    }    return 0;   }