[boost] BOOST_CHECK_EQUAL() dangers

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2002-11-20 09:37:15

Hi,

the (really useful!) boost test library provides the test tool macro 
BOOST_CHECK_EQUAL() which checks two values for equality. I just learned 
the hard way that the following does not do what one would expect.

char const *p = 0;
BOOST_CHECK_EQUAL(p, p);

On my system, this results in a test program crash. The reason is, for 
this parameter type strcmp() is called which (of course) doesn't like 
NULL pointers as it's arguments.

This isn't documented anywhere in the test library documentation 
(neither the special treatment of char * nor the requirement that those 
must not be NULL) and I think it needs to be fixed. There are several 
possible ways.

1. Just document it. Not so good, IMHO.

2. Document the special case and add a check for NULL pointers before 
calling strcmp().

3. Remove the special case alltogether. After all, I might want to check 
that the pointers are equal and not the string they point to. This might 
be the best solution, but breaks backward compatibility.

Markus