assert(3X)

assert -- verify program assertion

Synopsis

   #include <assert.h>
   
   void assert(int expression);

Description

This macro is useful for putting diagnostics into programs. When it is executed, if expression is false (zero), assert prints

   Assertion failed: expression, file xyz, line nnn

on the standard error output and aborts. In the error message, xyz is the name of the source file and nnn the source line number of the assert statement. The latter are respectively the values of the preprocessor macros __FILE__ and __LINE__.

Compiling with the preprocessor option -DNDEBUG [see cc(1)], or with the preprocessor control statement #define NDEBUG ahead of the #include assert.h statement, will stop assertions from being compiled into the program.

References

abort(3C), cc(1)

Notices

Since assert is implemented as a macro, the expression may not contain any string literals.