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return

Started by luasitdown Jan 30, 2006 at 3:51 AM 3 replies 450+ views

Original Post

Jan 30, 2006 at 3:51 AM

TYPE * boo() { if ( isTrue ) { ....... } } if isTrue is false, what value is return? it seem it is different according to release build or debug build. is that true? what is result of below, and WHY?


D3DXVECTOR3 boo()
{
	if (0 )
	{
		return D3DXVECTOR3(0,0,0);
	}
}
int main(int argc, char* argv[])
{
	D3DXVECTOR3  f = D3DXVECTOR3(33,33,33);
	f = boo();
}

MaulingMonkey

249

MaulingMonkey

Jan 30, 2006 at 3:56 AM

Quote:
Original post by luasitdown
TYPE * boo()
{
if ( isTrue )
{
.......
}

}

if isTrue is false, what value is return?

Undefined.

Quote:
it seem it is different according to release build or debug build. is that true?

It's quite possible. It's also quite possible for it to just crash. That function is badly written, it should return something, or stop on an assert or throw an exception.

etothex

Jan 30, 2006 at 4:14 AM

It will return garbage. And it will be very different between debug and release, and also between slightly different versions of almost the same program.

CTar

113

CTar

Jan 30, 2006 at 4:21 AM

As MaulingMonkey said, it's undefined, so it could make your computer catch fire, format you drives, but it will most likely return garbage memory, and maybe even destroy the stack for other functions (use a pop to get the return value, but there is no matching push).

Skeleton_V@T

Jan 30, 2006 at 4:38 AM

Quote:
Original post by luasitdown
TYPE * boo()
{
if ( isTrue )
{
.......
}

}

A good compiler will warn you something on the line: "Not all control paths return a value.".

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