Messages issued by syslog not showing up in system logs

Question

I'm having some trouble with <syslog.h> in 10.5. I'm writing a small fork based server for class and I want to use syslog() to print a bunch of debug info. However, I can't find any of the messages I issue via syslog() while using Console (I'm looking in both all messages & system.log).

Here is a code snippet of a plain C:

#include <syslog.h>
#include <stdarg.h>

int main (int argc, const char * argv[])
{
    openlog("Syslog Test", LOG_PID | LOG_NDELAY | LOG_CONS | LOG_PERROR, LOG_USER);
    setlogmask(LOG_UPTO(LOG_DEBUG));
    syslog(LOG_DEBUG, "%s", "Hello, World!");
    syslog(LOG_DEBUG, "%s", "And goodbye!");
    closelog();
    return 0;
}

And I don't see anything in "All Messages", "Console Messages" or system.log. Any advice?

Answer 1

Despite what you pass to setlogmask(), in its default configuration, OS X will only write messages to the system log that have a priority of LOG_NOTICE or higher.

Any of the following will solve your problem...

1. Enable lower-priority logging in /etc/syslog.conf -- kern.* is not enough, as log messages from Xcode are not coming from the kernel
2. Change the priority of your messages from LOG_DEBUG to LOG_NOTICE
3. Simply use the built-in Xcode console -- the output will always appear there regardless of your syslog.conf settings

Here's what it looks like in the built-in Xcode 4 console:

Also, if you're developing exclusively for OS X, you might want to look into ASL (Apple System Log), which was meant to replace syslog().