2.9BSD - /usr/include/assert.h

   1: #ifndef NDEBUG
   2: #define _assert(ex) {if (!(ex)){fprintf(stderr,"Assertion failed: file %s, line %d\n", __FILE__, __LINE__);exit(1);}}
   3: #define assert(ex)  {if (!(ex)){fprintf(stderr,"Assertion failed: file %s, line %d\n", __FILE__, __LINE__);exit(1);}}
   4: #else
   5: #define _assert(ex) ;
   6: #define assert(ex)  ;
   7: #endif

Defined macros

Usage of this include