Simple syslog example

01-test.c

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

int main()
{
 openlog("fig3-7", LOG_PERROR | LOG_PID | LOG_NDELAY, LOG_USER);
 syslog(LOG_NOTICE, "Hello Syslog!");
 syslog(LOG_INFO, "Here's an informational message.");
 syslog(LOG_WARNING, "Here's a warning.");
 syslog(LOG_ERR, "Here's an error.");
 syslog(LOG_DEBUG, "Here's some debugging information.\n");

 for (int i = 0; i < 10000000; ++i)
 {
   syslog(LOG_DEBUG, "%i", i);
   sleep(1);
 }
 closelog();
 exit(EXIT_SUCCESS);
}

02-output.txt

fig3-7[8726]: Hello Syslog!
fig3-7[8726]: Here's an informational message.
fig3-7[8726]: Here's a warning.
fig3-7[8726]: Here's an error.
fig3-7[8726]: Here's some debugging information.
fig3-7[8726]: 0
fig3-7[8726]: 1
fig3-7[8726]: 2
fig3-7[8726]: 3
fig3-7[8726]: 4
.
.
.