assert(3X)                                             assert(3X)



     NAME
          assert - verify program assertion

     SYNOPSIS
          #include <assert.h>

          assert(expression)
          int expression;

     DESCRIPTION
          This macro is useful for putting diagnostics into programs.
          If expression is false (zero) when assert is executed, as-
          sert prints

             Assertion failed: expression, file xyz, line nnn

          on the standard error output and aborts.  In the error mes-
          sage, xyz is the name of the source file and nnn is the
          source line number of the assert statement.

          Compiling with the preprocessor option -DNDEBUG (see cpp(1))
          or with the preprocessor control statement #define NDEBUG
          ahead of the #include <assert.h> statement, stops assertions
          from being compiled into the program.

     NOTES
          assert cannot be used in an expression since it turns into
          an if statement.

     SEE ALSO
          cpp(1), abort(3C).
























     April, 1990                                                     1