A question of fork() function

[bite me if you can...]

The man page of fork() says that the file descriptor are shared by
parent process & childern processes, so any operation of file
descriptor will affect them both.
But why the behavior of FILE doesn't like file descriptors?

This is my program, the result of operation of file descriptor is
ideal, but result of operation of FILE is amazing...
int fd=-1, pid;
FILE *fin=(FILE *)NULL;

fd=open("mem.tmp", O_RDWR);
fin=fopen("mem1.tmp", "r");
pid=fork();
if(pid) {
printf("(parent)\n");
printf("(parent) lseek(): %d\n", lseek(fd, 10, SEEK_SET));
fseek(fin, 10, SEEK_SET);
printf("(parent) ftell(): %d\n", ftell(fin));
}
else {
printf("(child)\n");
printf("(child)\n");
printf("(child) ftell(): %d\n", ftell(fin));
}

 

[Artie Gold]

The man page of fork() says that the file descriptor are shared by
parent process & childern processes, so any operation of file

[snip]

....where things like fork() are *on*-topic.

HTH,
--ag

 

[Keith Thompson]

The man page of fork() says

[...]

fork(), like mmap(), is not a standard C function. Try
comp.unix.programmer.

 

[SM Ryan]

# The man page of fork() says that the file descriptor are shared by
# parent process & childern processes, so any operation of file
# descriptor will affect them both.
# But why the behavior of FILE doesn't like file descriptors?

FILEs aren't file descriptors. They have additional buffering
and other attributes. If you want to multitask, like fork or
threads, you need to check your system's documentation how these
interact with stdio.