UsingSyslog - Revision history

FabienM: /* Basis */

2013-10-16T14:51:19Z

‎Basis

FabienM: /* Buildroot packages */

2013-09-12T08:24:00Z

‎Buildroot packages

FabienM at 08:20, 12 September 2013

2013-09-12T08:20:33Z

JulienB: /* Calling syslog method from your C source code */

2012-09-21T12:40:23Z

‎Calling syslog method from your C source code

SebastienR at 16:53, 19 September 2012

2012-09-19T16:53:04Z

SebastienR: New page: ==Calling syslog method from your C source code== This part is quiet simple, but we need to correctly use each parameter. First step is to declare us as syslog client : ....

2012-09-19T16:50:53Z

New page: ==Calling syslog method from your C source code== This part is quiet simple, but we need to correctly use each parameter. First step is to declare us as syslog client : <source lang="C"> ....

New page

==Calling syslog method from your C source code==
This part is quiet simple, but we need to correctly use each parameter.
First step is to declare us as syslog client :
<source lang="C">
...
#include <syslog.h>

int main(int argc, char *argv[])
{
...
openlog("program_name", LOG_PID, LOG_USER);
...
closelog();
...
}
</source>
Then, you can call syslog from your code using printf like format :
<source lang="C">
...
syslog(LOG_INFO, "%s called with %d arguments\n", argv[0], argc);
...
</source>
if you compile the source file:
<source lang="C">
// log_syslog.c
#include <syslog.h>

int main(int argc, char *argv[])
{
openlog("program_name", LOG_PID, LOG_USER);
syslog(LOG_INFO, "%s called with %d arguments", argv[0], argc - 1);
closelog();

return 0;
}
</source>
With the command :
<pre class="apf">
itsme@mycomputer:~/log_syslog$ gcc log_syslog.c -o log-syslog
</pre>
Then run it 2 times :
<pre class="apf">
itsme@mycomputer:~/log_syslog$ ./log_syslog
itsme@mycomputer:~/log_syslog$ ./log_syslog pim pam poum
</pre>
You will probably obtain no result in shell, but you can take a look in you're system log (/var/log/syslog or /var/log/messages)
<pre class="apf">
itsme@mycomputer:~/log_syslog$ tail -n 2 /var/log/syslog
Sep 19 18:46:49 mycomputer program_name[3022]: ./log_syslog called with 0 arguments
Sep 19 18:46:53 mycomputer program_name[3023]: ./log_syslog called with 3 arguments
</pre>
We can notice, that the lines contain program_name[PID] pattern showing us the name we have specified in openlog and the pid of the process because we ask it with LOG_PID argument.

← Older revision		Revision as of 14:51, 16 October 2013
Line 1:		Line 1:
	= Basis =		= Basis =
		+	==Calling syslog method from shell==
		+	To do that, use '''logger''' command :
		+	<pre class="target">
		+	# logger -t "MYTAGNAME" "I like otters with cream"
		+	</pre>
		+
		+	You can then see the message in /var/log/messages:
		+	<pre class="target">
		+	# tail /var/log/messages
		+	...
		+	Oct 16 16:50:13 armadeus user.notice MYTAGNAME: I like otters with cream
		+	</pre>

	==Calling syslog method from your C source code==		==Calling syslog method from your C source code==

@@ Line 77: / Line 77: @@
 </pre>
-Then select option :
+Select option :
 <pre class="config">
 </pre>

@@ Line 1: / Line 1: @@
 ==Calling syslog method from your C source code==
 This part is quite simple, but we need to correctly use each parameter.
@@ Line 50: / Line 52: @@
 </pre>
 We can notice, that the lines contain program_name[PID] pattern showing us the name we have specified in openlog and the pid of the process because we ask it with LOG_PID argument.

@@ Line 21: / Line 21: @@
      ...
 </source>
-if you compile the source file:
+If you compile the source file:
 <source lang="C">
 // log_syslog.c
@@ Line 28: / Line 28: @@
 int main(int argc, char *argv[])
+{
-	openlog("program_name", LOG_PID, LOG_USER);
+    openlog("program_name", LOG_PID, LOG_USER);
-	syslog(LOG_INFO, "%s called with %d arguments", argv[0], argc - 1);
+    syslog(LOG_INFO, "%s called with %d arguments", argv[0], argc - 1);
-	closelog();
+    closelog();
+    return 0;
-	return 0;
+}
 </source>
@@ Line 44: / Line 43: @@
 itsme@mycomputer:~/log_syslog$ ./log_syslog pim pam poum
 </pre>
-You will probably obtain no result in shell, but you can take a look in you're system log (/var/log/syslog or /var/log/messages)
+You will probably obtain no result in shell, but you can take a look in your system log (/var/log/syslog or /var/log/messages)
 <pre class="apf">
 itsme@mycomputer:~/log_syslog$ tail -n 2 /var/log/syslog