Why do you think the compiler with optimizations will remove the assertion? The ...

tptacek · on Jan 10, 2012

Production code is supposed to define away the assertions. It is an actual error to manage important program state with asserts.

(That doesn't make these particular asserts an error).

zedshaw · on Jan 11, 2012

In the earlier chapters they setup a Makefile with full debugging on so these don't get removed. It's mostly just for this one exercise, and in the rest of the book they use a set of debug macros I wrote:

http://c.learncodethehardway.org/book/learn-c-the-hard-waych...

scott_s · on Jan 10, 2012

In support of tptacek's comment, an abbreviate version of what's in assert.h on my OSX system:

  #ifdef NDEBUG
  #define assert(e)   ((void)0)
  #else

  #define assert(e)  \
    ((void) ((e) ? 0 : __assert (#e, __FILE__, __LINE__)))
  #define __assert(e, file, line) \
    ((void)printf ("%s:%u: failed assertion `%s'\n", file, line, e), abort())

So, if NDEBUG ("no debug") is defined, which it is if optimizations are turned on, asserts become a no-op.