Thread: give my pointer strlen 0

Is this the best (only?) way to give a fresh char *ptr a strlen of 0?

Code:

ptr=malloc(0); free(ptr);

So it has to malloc'd anyway? I might as well just use the free call then.

Just assign "" to it.

Originally Posted by King Mir

Just assign "" to it.

oh you're right -- King Mir wins

thanks

From the standard

Originally Posted by 7.20.3 C99

...
If the size of the space requested is zero, the behavior is
implementation-defined: either a null pointer is returned, or the
behavior is as if the size were some nonzero value, except that the
returned pointer shall not be used to access an object.

In other words, it could end up pointing anywhere. So strlen() would probably segfault and/or return unpredictable results.

The best way (IMO) is what Codeplug suggested:

Code:

char * ch = malloc(1);
if(ch == NULL)
{
   /* do something */
}

*ch = '\0';

/* ... do whatever with ch, resize if need be */

free(ch);

It doesn't have to be on the heap either (which is pretty obvious )

Code:

char nul = '\0';
char * ch = &nul;

/* do whatever with ch */