(char *)(-1)

[david Fridley]

In article <18792 at mimsy.UUCP>, chris at mimsy.UUCP (Chris Torek) writes:
> >>... if NULL is returned there was an error getting the next string,
> >>if (-1) is returned there were no more symbols.
> 
> >Is it safe to return -1?
> 
To quote from the my UNIX System V (Release 3.0) Programmers Reference manual
for BRK(2) (page 141):

NAME
	brk,sbrk - change data segment allocation
SYNOPSIS
	int brk (endds)
	char *endds;

	char *sbrk (incr)
	int incr;
		:
		:

DIAGNOSTICS
    Upon successful completion, brk returns a value 0 and sbrk returns the old
    break value.  Otherwise, a value of -1 is returned and errno is set to 
    indicate the error.

Here we see that sbrk(), a standard UNIX function, which returns a character
pointer will return (-1).  This is the functioin used by malloc() to get 
free more free memory from the operation system.


-- 
david.
DISCLAIMER: If it's important have a backup.  If it ain't broke don't fix it.
Proceed at your own risk.  My oponions are MY own.  Spelling does not count.
My fondest dream is to leave this planet.