Date:	Thu, 29 Jul 1999 11:03:50 +0300 (IDT)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	Dan Gold <TedMat AT CoastNet DOT com>
cc:	djgpp AT delorie DOT com
Subject:	Re: Detecting a 0 and also a letter in atoi()
In-Reply-To:	<199907281320.JAA24759@delorie.com>
Message-ID:	<Pine.SUN.3.91.990729110332.25908H-100000@is>
MIME-Version:	1.0
Reply-To:	djgpp AT delorie DOT com
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On Tue, 26 Jan 1999, Dan Gold wrote:

> Could be offtopic, but It I want to detect if there is a letter in my
> character boxes but atoi returns zero if there is a letter. This is poorly
> designed because I can't use the number 0 when converting the integer
> string to an int variable.

`atoi' is one of the oldest functions in standard C libraries, so it
has to be compatible with its original design, since there are gobs of
programs out there which rely on this behavior.

If you need a conversion function that will also tell you when the
string is not a number, use `strtol'.  It returns a pointer to the
first character in the string that it couldn't convert.  If this
pointer points to something other than the terminating null character,
you know there's a non-digit in the input string.

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