include/assert.h

   1 /* The <assert.h> header contains a macro called "assert" that allows
   2  * programmers to put assertions in the code.  These assertions can be verified
   3  * at run time.  If an assertion fails, an error message is printed and the
   4  * program aborts.
   5  * Assertion checking can be disabled by adding the statement
   6  *
   7  *      #define NDEBUG
   8  *
   9  * to the program before the
  10  *
  11  *      #include <assert.h>
  12  *
  13  * statement.
  14  */
  15
  16 #undef assert
  17
  18 #ifndef _ANSI_H
  19 #include <ansi.h>
  20 #endif
  21
  22 #ifdef NDEBUG
  23 /* Debugging disabled -- do not evaluate assertions. */
  24 #define assert(expr)  ((void) 0)
  25 #else
  26 /* Debugging enabled -- verify assertions at run time. */
  27 #ifdef _ANSI
  28 #define __makestr(x)    # x
  29 #define __xstr(x)       __makestr(x)
  30
  31 _PROTOTYPE( void __bad_assertion, (const char *_mess) );
  32 #define assert(expr)    ((expr)? (void)0 : \
  33                                 __bad_assertion("Assertion \"" #expr \
  34                                     "\" failed, file " __xstr(__FILE__) \
  35                                     ", line " __xstr(__LINE__) "\n"))
  36 #else
  37 #define assert(expr) ((void) ((expr) ? 0 : __assert( __FILE__,  __LINE__)))
  38 #endif /* _ANSI */
  39 #endif