09-28-2010
Quote:
Originally Posted by
Mercfh
That makes sense.
Oh well I mean everything else looks correct, the myshell> printout is a little bit screwy when I use & BUT the & seems to be working correctly regardless (using the sleep 60 & thing to test it)
You may be fighting buffers because you're using printf(). This keeps it in memory until it decides it's convenient to print it(usually, whenever it finds a newline). And when you fork(), you get a close-to-identical copy... So if you fork while anything's in the buffer it could even get printed twice! You might want to fflush(stdout); after you print, and before you fork(), to guarantee nothing's left in the buffers.
You can also do fprintf(stderr, "hello world\n"); to avoid it, since stderr never buffers. (it might be better to print to stderr anyway.)
Last edited by Corona688; 09-28-2010 at 04:11 PM..
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SLEEP(3) Linux Programmer's Manual SLEEP(3)
NAME
sleep - Sleep for the specified number of seconds
SYNOPSIS
#include <unistd.h>
unsigned int sleep(unsigned int seconds);
DESCRIPTION
sleep() makes the calling thread sleep until seconds seconds have elapsed or a signal arrives which is not ignored.
RETURN VALUE
Zero if the requested time has elapsed, or the number of seconds left to sleep, if the call was interrupted by a signal handler.
CONFORMING TO
POSIX.1-2001.
BUGS
sleep() may be implemented using SIGALRM; mixing calls to alarm(2) and sleep() is a bad idea.
Using longjmp(3) from a signal handler or modifying the handling of SIGALRM while sleeping will cause undefined results.
SEE ALSO
alarm(2), nanosleep(2), signal(2), signal(7)
COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU
2010-02-03 SLEEP(3)