C函数_fileno了解

int _fileno(FILE *stream );  ----->Gets the file descriptor associated with a stream.（用来取得参数stream指定的文件流所使用的文件描述符）

#include<stdio.h>

返回值：某个数据流的文件句柄

DEMO:MSDN上的例子

#include <stdio.h>#include <process.h>int main(){printf("The file descriptor for stdin is %d\n",_fileno(stdin));printf("The file descriptor for stdout is %d\n",_fileno(stdout));printf("The file descriptor for stderr is %d\n",_fileno(stderr));system("pause");return 0;}

DEMO2:

#include <stdio.h>#include <process.h>int main(){FILE *fp=NULL;int file_handle;fp=fopen("fileno.c","r");if (fp==NULL){fprintf(stderr,"it's a error!\n");getchar();return -1;}    file_handle=_fileno(fp);printf("fd=%d\n",file_handle);fclose(fp);fp=NULL;system("pause");return 0;}

【FROM MSDN &&百科】