Difference between DEBUG and NDEBUG?

[Alexander Malkis]

Why do programmers like to use NDEBUG instead of DEBUG?

 

[Victor Bazarov]

Why do programmers like to use NDEBUG instead of DEBUG?

That's a strange question. 'DEBUG' is usually for debugging. 'NDEBUG'
is defined when the debugging is done with. It means "NO DEBUG".

V

 

[Leor Zolman]

Why do programmers like to use NDEBUG instead of DEBUG?

It isn't that we /like/ to, it's because that's the symbol that the
preprocessor code in <assert.h> / <cassert> specifically looks for to
disable assertions.

Remember, don't shoot the messenger ;-)
-leor

 

[Alf P. Steinbach]

That's a strange question. 'DEBUG' is usually for debugging. 'NDEBUG'
is defined when the debugging is done with. It means "NO DEBUG".

The standard assert macro is required to use NDEBUG. I don't think DEBUG
is mentioned anywhere in the standard. Too lazy to check, though... ;-)

 

[Victor Bazarov]

The standard assert macro is required to use NDEBUG. I don't think DEBUG
is mentioned anywhere in the standard. Too lazy to check, though... ;-)

No, it's not defined anywhere. Many do still use it (or some variations
of it), I believe. "Everything is allowed if not expressly prohibited".

 

[Mike Wahler]

Why do programmers like to use NDEBUG instead of DEBUG?

NDEBUG is a macro defined by the standard, DEBUG is not.

-Mike

 

[E. Robert Tisdale]

Why do programmers like to use NDEBUG instead of DEBUG?

ASSERT(3) Linux Programmer’s Manual ASSERT(3)

NAME
assert - abort the program if assertion is false

SYNOPSIS
#include <assert.h>

void assert(scalar expression);

DESCRIPTION
If the macro NDEBUG was defined at the moment <assert.h> was last
included, the macro assert() generates no code, and hence does
nothing at all. Otherwise, the macro assert() prints an error
message to standard output and terminates the program by calling
abort() if expression is false (i.e., compares equal to zero).

The purpose of this macro is to help the programmer find bugs in
his program. The message "assertion failed in file foo.c,
function do_bar(), line 1287" is of no help at all to a user.


The assert debugging mechanism was designed to be *on* by default.
You must define NDEBUG to turn it off.