Question

So I have a daemon running on a Linux system, and I want to have a record of its activities: a log. The question is, what is the ‘best’ way to accomplish this?

My first idea is to simply open a file and write to it.

FILE* log = fopen('logfile.log', 'w'); /* daemon works...needs to write to log */ fprintf(log, 'foo%s\n', (char*)bar); /* ...all done, close the file */ fclose(log); 

Is there anything inherently wrong with logging this way? Is there a better way, such as some framework built into Linux?

Answer 1

Unix has had for a long while a special logging framework called syslog. Type in your shell

man 3 syslog 

and you’ll get the help for the C interface to it.

Some examples

#include <stdio.h> #include <unistd.h> #include <syslog.h>  int main(void) {   openlog('slog', LOG_PID|LOG_CONS, LOG_USER);  syslog(LOG_INFO, 'A different kind of Hello world ... ');  closelog();   return 0; }