07-04-2010
Quote:
Originally Posted by
fpmurphy
Yes, it is very possible for that to happen.
I am not sure what your understanding of how pthread_cond_timedwait works is. I would point out that once the wait time expires and is turned off, the thread is moved off the sleep queue. Likewise once a sleeping thread is signaled, even by error, it is taken off the sleep queue and the wait timer is turned off. This does not mean that it re-acquires the mutex, etc. If it takes another week before reacquiring the mutex, too bad. If it never gets the mutex back because the other thread has not released it, too bad.
i see that your understanding is then the same as mine.
realizing this detail in pthread (at least for the implementation i'm using) was a bit of a surprise. i try to use timed calls (pass timeout) just to be sure that the application will give a last sign of failure before giving up, instead of blocking there silent for ever.
Quote:
Originally Posted by
fpmurphy
If you have the Lewis & Berg book on Pthreads, this issue is discussed on pages 94 -99. Dave Butenhof also discusses this issue in his book on Pthreads. See section 3.3.2 et al.
BTW, a thought just struck me, are you trying to port a Win32 application which uses eventing to GNU/Linux?
fortunately no!
9 More Discussions You Might Find Interesting
1. AIX
Hi all, my RS/6k 7043 150 with aix 4.3.3 takes FOREVER to log in. When I power the machine on, the boot process procedes normally and I get 2 short beeps (which I don't recall hearing before) and then I get the login window. If I log in, as root, say, the machine goes to its usual blue screen... (3 Replies)
Discussion started by: Jwoollard
3 Replies
2. Programming
When I am using msgrcv to get a message from a queue, in case of msgsnd some error, the msgrcv thread will waiting forever.
Is there some way that I can specify a time out value for this queue ? just let msgrcv wait for some time, if no message comes during this time slot, msgrcv just return... (3 Replies)
Discussion started by: Yun Gang Chen
3 Replies
3. Solaris
Hi I am very new for Solaris, I want to make some users' passwords never expired. My ssytem kernel is: 5.8
# uname -a
SunOS sspfs_svr 5.8 Generic_117000-01 sun4u sparc SUNW,Netra-240
Could you make some advice?
Thanks (5 Replies)
Discussion started by: xramm
5 Replies
4. Linux
Hi guys! I've just mounted my drive in fstab:
/dev/sdb /myfolder ext3 defaults 0 0
and rebooted linux.
I've got severel failers during booting process and also I can't login as root first time:
login: root
password:root
incorrect login
login:user
password: user
... (1 Reply)
Discussion started by: Junior Admin
1 Replies
5. IP Networking
Just looking at my ethernet interface.. I see this response... what does this mean...?
ipconfig...
lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft... (0 Replies)
Discussion started by: jimmyc
0 Replies
6. Programming
I need to use pthread_cond_timedwait, which is available in my old embedded Linux for PPC. But I don't have clock_gettime... So, I build this replacement for clock_gettime, and it seems to work:
#include <sys/time.h>
#include <time.h>
int clock_gettime_replacement(struct timespec *now) {... (1 Reply)
Discussion started by: fcolombo
1 Replies
7. Shell Programming and Scripting
I'm trying to make a little script, but I have a problem...
I'm trying to sed a list of files made with a ls > filename.txt...
Two variables (or i may call them constant because they are fixed values :D):
ststr1 and ststr2
I want to
sed s/"$ststr1"/"$ststr2"/g filename.txt >... (5 Replies)
Discussion started by: maxlamax
5 Replies
8. Red Hat
Hello All,
I was trying to install one rpm and it failed due to missing dependencies, when I try to look at the dependencies and try to install them it is asking for 100+ dependencies, did any one ever face this problem? how can we fix this?
rpm -ivh /var/tmp/erlang-R15B-02.1.el6.x86_64.rpm... (0 Replies)
Discussion started by: lovesaikrishna
0 Replies
9. UNIX for Dummies Questions & Answers
I am trying to use the forever command. I can get it to work if I do not use the w option to watch for changes and cause an automatic restart on a change to the contents of the directory being watched.
I would really like to use the watch option. Is this option fully implemented? here is an... (4 Replies)
Discussion started by: barrygordon
4 Replies
LEARN ABOUT OSX
pthread_cond_wait
PTHREAD_COND_WAIT(3) BSD Library Functions Manual PTHREAD_COND_WAIT(3)
NAME
pthread_cond_wait -- wait on a condition variable
SYNOPSIS
#include <pthread.h>
int
pthread_cond_wait(pthread_cond_t *restrict cond, pthread_mutex_t *restrict mutex);
DESCRIPTION
The pthread_cond_wait() function atomically unlocks the mutex and blocks the current thread on the condition specified by the cond argument.
The current thread unblocks only after another thread calls pthread_cond_signal(3) or pthread_cond_broadcast(3) with the same condition vari-
able. The mutex must be locked before calling this function, otherwise the behavior is undefined. Before pthread_cond_wait() returns to the
calling function, it re-acquires the mutex.
RETURN VALUES
If successful, the pthread_cond_wait() function will return zero; otherwise, an error number will be returned to indicate the error.
ERRORS
pthread_cond_wait() will fail if:
[EINVAL] The value specified by cond or the value specified by mutex is invalid.
SEE ALSO
pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_init(3), pthread_cond_signal(3), pthread_cond_timedwait(3)
STANDARDS
pthread_cond_wait() conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').
Darwin November 5, 2001 Darwin