Howto Auto launch a C Program on startup.

[lilzz]

I am making a C program and would like to auto run on startup.

How I can accomplish that?

Also on my program I have a loop checking forever to see if certain pin becoming low.

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 while (1)
    {
	if (bcm2835_gpio_eds(PIN))
	{
	    // Now clear the eds flag by setting it to 1
	    bcm2835_gpio_set_eds(PIN);
	    printf("low event detect for pin 15\n");
	}

	// wait a bit
	delay(500);
    }

[DougieLawson]

Add a script called /etc/init.d/scriptnamehere
Activate it with update-rc.d scriptnamehere enable

There's a skeleton /etc/init.d/skeleton to show how to construct those scripts.

[lilzz]

Hi, Mine is a C Program not a script, would that still apply from above info?

[shuckle]

Just call it from /etc/rc.local

[DougieLawson]

Just call it from /etc/rc.local

That's ok when you have one simple thing to call, but when you add the code to run your fifth, tenth or twentieth process you're going to curse not doing it the "right" way.

rc.local is a tactical solution, init scripts are the strategic way.

It doesn't matter what programming language it runs like a bash shell script with root (uid0) privileges.

[hampi]

The daemons like 'httpd' or 'atd' are programs like that. My program 'pipicpowerd' is one example of a DIY daemon:

https://github.com/oh7bf/PiPIC/tree/master/pipicpowerd

The process for creating own daemon is about following: First write a short manual page to describe what the program is supposed to do. This can be updated later when you modify the code or add new features to it. Then write the skeleton for the daemon. This has the logging function that is needed for the debugging. Write a short Makefile to compile the code. Compile the code and try that it works. The logfile should have some comment like

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2013 Dec 24 10:00:00 mydaemon started

and

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2013 Dec 24 10:00:30 mydaemon stopped

when you kill the daemon process with

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kill -s SIGTERM

. Now you are ready to write the first code that is doing something useful. Add only one new feature at a time and test it immendiately to see that the program is still working as it should.