Re: problem with malloc?

[Kaz Kylheku <kaz at ashi dot footprints dot net>]

On Sun, 23 Apr 2000, Kervin wrote:

> Date: Sun, 23 Apr 2000 16:48:53 -0400 (EDT)
> From: Kervin <kpierre@winnie.fit.edu>
> Reply-To: glibc-linux@ricardo.ecn.wfu.edu
> To: glibc-linux@ricardo.ecn.wfu.edu
> Cc: Kaz Kylheku <kaz@ashi.footprints.net>
> Subject: Re: problem with malloc?
> 
> 
> > target = ( char * )malloc( (len+1)*sizeof( char ) );
> > strncpy( target, buffer, len );
> 
> target = strdup(buffer);

Note that although strdup is a function in glibc, it is not a standard C
function. It is easy to write a tiny function that does what strdup does,
so there is little excuse for introducing a system depenency.

Also note that sizeof (char) is, by definition, one. 

> or...
> 
> target = ( char * )malloc( (len+1)*sizeof( char ) );
> memset(target, '\0',len+1);
> strcpy( target, buffer);
> 
> when not sure, memset! : )

When not sure, think harder until sure. This memset is a complete waste of
cycles. The strcpy function does not require its target buffer to be
zero-filled, but merely large enough to hold a copy of the entire string.  
It does require a valid pointer, however. The malloc function may return
null and that needs to be tested before using the pointer.