Getfileflags.c

#include "apue.h" 
#include < fcntl.h> 
int
main(int argc, char *argv[])
{
    int val;
    if (argc != 2)
        err_quit("usage: a.out <descriptor#>");
    if ((val = fcntl(atoi(argv[1]), F_GETFL, 0)) < 0)
        err_sys("fcntl error for fd %d", atoi(argv[1]));
    switch (val & O_ACCMODE)
    {
    case O_RDONLY:
        printf("read only");
        break;
    case O_WRONLY:
        printf("write only");
        break;
    case O_RDWR:
        printf("read write");
        break;
    default:
        err_dump("unknown access mode");
    }
    if (val & O_APPEND)
        printf(", append");
    if (val & O_NONBLOCK)
        printf(", nonblocking");
    if (val & O_SYNC)
        printf(", synchronous writes");
#if !defined(_POSIX_C_SOURCE) && defined(O_FSYNC) && (O_FSYNC != O_SYNC) if (val & O_FSYNC)
    printf(", synchronous writes");
#endif putchar(’\n’);
    exit(0);
}