assert(3X)

NAME
     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.

SEE ALSO
     cc(1), abort(3C)

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