buf.c

unix环境高级编程的源代码

#include    "ourhdr.h"
void    pr_stdio(const char *, FILE *);
int
main(void)
{
    FILE    *fp;

    fputs("enter any character\n", stdout);
    if (getchar() == EOF)
        err_sys("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)
        err_sys("fopen error");
    if (getc(fp) == EOF)
        err_sys("getc error");
    pr_stdio("/etc/motd", fp);
    exit(0);
}
void
pr_stdio(const char *name, FILE *fp)
{
    printf("stream = %s, ", name);
                /* following is nonportable */
    if      (fp->_flags & _IOLBF)    printf("line buffered");
    else if (fp->_flags & _IONBF)    printf("unbuffered");
    else /* if neither of above */    printf("fully buffered");
    printf(", buffer flag = %d\n", fp->_flags & 0xff);
}