BOOST_STATIC_ASSERT without boost

Konstantin picture Konstantin · Dec 30, 2009 · Viewed 9.3k times · Source

Since boost is forbidden in a company I work for I need to implement its functionality in pure C++. I've looked into boost sources but they seem to be too complex to understand, at least for me. I know there is something called static_assert() in the C++0x standart, but I'd like not to use any C++0x features.

Answer

AProgrammer picture AProgrammer · Dec 30, 2009

One other trick (which can be used in C) is to try to build an array with a negative size if the assert fail:

#define ASSERT(cond) int foo[(cond) ? 1 : -1]

as a bonus, you may use a typedef instead of an object, so that it is usable in more contexts and doesn't takes place when it succeed:

#define ASSERT(cond) typedef int foo[(cond) ? 1 : -1]

finally, build a name with less chance of name clash (and reusable at least in different lines):

#define CAT_(a, b) a ## b
#define CAT(a, b) CAT_(a, b)
#define ASSERT(cond) typedef int CAT(AsSeRt, __LINE__)[(cond) ? 1 : -1]