logmask.c

#include <syslog.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

int main()
{
    int logmask;

    openlog("logmask", LOG_PID | LOG_CONS, LOG_USER);
    syslog(LOG_INFO, "informative message, pid = %d", getpid());
    syslog(LOG_DEBUG, "debug message, should appear");
    logmask = setlogmask(LOG_UPTO(LOG_NOTICE));
    syslog(LOG_DEBUG, "debug message, should not appear");
    exit(0);
}