void main returning int - why compiles?

Jonathan M Davis jmdavisProg at gmx.com
Sat Jan 1 00:32:17 PST 2011

On Friday 31 December 2010 23:37:17 Daren Scot Wilson wrote:
> I'm wondering why the following compiles.  I'm using LDC.  Perhaps it's a
> bug, or there's some subtlety about D.   I have deliberately, out of a
> combination of idleness and desire for mischief, have  main()  declared as
> returning void, but with a return statement giving an integer.
> If the first "half evil" return statement is uncommented, the corruption is
> noticed by the compiler and it writes an error.
> As shown, the "total evil" return statement gets a value from subroutine
> foo().  Being somehow so perfect in its evilness, this passes through the
> compiler without a burp.  The resulting executable returns zero (or my bash
> shell defaults to zero when receiving nothing.)
> When I get religion and like good boy declare main() as returing int, it
> compiles in perfectly.  When executed, the program returns either number
> according to which return statement is uncommented.
> int foo(int x)   {
> 	return x;
> }
> void main()   {
> 	// return 333;   /* half evil */
> 	return foo(666);  /* total evil */
> }

I don't know what LDC's current state is in terms of being up-to-date with the 
latest D. However, it is _not_ legal D to return a value from a void function. 
So, this is definitely a bug in LDC.

- Jonathan M Davis

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