One way to solve the do/while(0) problem is by using a “statement expression”. It's a GCC extension, and I don't know the reason it has never been accepted into

One way to solve the do/while(0) problem is by using a “statement expression”. It's a GCC extension, and I don't know the reason it has never been accepted into the standard. Here's how it works: #define my_assert(X) ({ if (!(X)) error(); }) Another way is to use a lambda expression, and then call it immediately: #define my_assert(X) ( [=]() { if (!(X)) error(); } )() Because the lambda captures by copy, it will catch inadvertent side effects in some cases. You can also use the conditional operator in this case: #define my_assert(X) ( (X) ? error() : ((void)0) )