4.10.1 assert

assert(expression)

The assert() macro tests the given expression and if it is false, the calling process is terminated. A diagnostic message is written to stderr and the function abort() is called, effectively terminating the program.

If expression is true, the assert() macro does nothing.

The assert() macro may be removed at compile time by defining NDEBUG as a macro (e.g., by using the compiler option -DNDEBUG).