判断标准I/O的缓冲区类型

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#include <stdio.h>

void
pr_stdio(const
char *, FILE
*);

int main()

{

    FILE
*fp;

    fputs("enter any character\n",stdout);

    if(getchar()==EOF)

        printf("getchar error");

    fputs("one line to standard error\n",stderr);

    pr_stdio("stdin",stdin);

    pr_stdio("stdout",stdout);

    pr_stdio("stderr",stderr);

    if((fp=fopen("/etc/motd","r"))==NULL)

        printf("fopen error");

    if(fgetc(fp)==EOF)

        printf("getc error");

    pr_stdio("/etc/motd",fp);

    return
0;

}

void
pr_stdio(const
char *name, FILE
*fp)

{

    printf("stream=%s, ",name);

    if(fp->_flags & _IO_UNBUFFERED)

        printf("unbuffered");

    else
if(fp->_flags & _IO_LINE_BUF)

        printf("line buffered");

    else

        printf("fully buffered or modified");

    printf(",buffer size = %d\n",fp->_IO_buf_end-fp->_IO_buf_base);

}