Advent4 patch, second try

Luis Javier Merino ljmerino at
Wed Sep 26 19:43:52 CEST 2007

On 9/26/07, Stefan Sperling <stsp at> wrote:
> And it's lazy and stupid not to test the condition explicitely.
> Something like:
>         if ((sptr = strchr(username, '\n')) != NULL)
> is easier to understand for humans and the same to the compiler.

Sure. Use NULL for comparing against pointers. For integers the UNIX
convention is returning -1 on errors, so compare using "< 0".

> Or simply avoid assigning inside a conditional statement altogether.
> Even if just not to confuse newbies reading the code.

Fine, it can also make code more readable by virtue of having shorter
code lines.

> If you need to know tons of crazy idioms to read code,
> it's not well written. This attiude leads to brain-damaged
> stuff like using

But knowing some idioms is valuable to be able to read other people's
sources, assignment inside an if condition is one of those idioms.

>         *((char *) mempcpy (dst, src, n)) = '\0';
> to copy a string.
> (see

:)  You're criticizing Ulrich Drepper.

Jonathan, if you're learning C, that's a good thread to read. Bottom
line: str* functions are a bad idea, programs wich do heavy string
processing should use dynamically allocated strings (or a language
other than C), as an example qmail and postfix implement their own
string handling functions.

> > Aside from that, I wouldn't really lose time fixing warnings on  code
> > written for pre-ANSI compilers.
> True, but at the same time these warnings are quite annoying.

I just think it's more useful to learn to remove warnings from more
modern programs, which are more likely to reflect code defects and not
code archaicisms.

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