exit() and return() in a C program

[Dr Gareth J. Barker]

Can somebody explain to me what the lint message below means?

	titan% cat test.c
	main()
	{
	}
	titan% lint test.c
	test.c(3): warning: main() returns random value to invocation
	environment
	titan% 
    titan% cat test1.c
    void exit();

	main()
	{
		exit(0);
	}
	titan% lint test1.c
	test.c(6): warning: main() returns random value to invocation environment

Replacing exit by return makes lint happy.

	titan% cat test2.c
	main()
	{
		return(0);
	}
	titan% lint test2.c
	titan% 

Is lint just trying to tell me that any function, including main, must
have at least one 'normal' return?  Is this a new feature in 4.1, I
don't remember seeing this before?

-- 
Gareth J. Barker,
Institute of Neurology, Queen Square,
London, UK.

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