Re: [Outreachy] Return value before or after free()?

On Jan 06 2020, Jeff King wrote:

On Mon, Jan 06, 2020 at 10:15:53PM +0100, Miriam R. wrote:

quoted

in run-command.c file `exists_in_PATH()` function does this:

static int exists_in_PATH(const char *file)
{
char *r = locate_in_PATH(file);
free(r);
return r != NULL;
}

I wonder if it is correct to do return r != NULL; after free(r);

It is technically undefined behavior according to the C standard, but I
think it would be hard to find an implementation where it was not
perfectly fine in practice.

Compilers get constantly better at exploiting undefined behaviour, so I
would not count on it.

Andreas.

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Andreas Schwab, schwab@linux-m68k.org
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