Subject: Re: strtonum(3) in our libc
To: Mindaugas <firstname.lastname@example.org>
From: Jason Thorpe <email@example.com>
Date: 06/05/2006 11:43:32
On Jun 2, 2006, at 5:16 PM, Mindaugas wrote:
> some time ago OpenBSD developers implemented strtonum(3) function
> is safer implementation of atoi(3) and strtol(3) - it does bounds
> checking, error detection, etc. They use it several applications (e.g.
> OpenSSH has native implementation).
> This function doesn't conform to POSIX or any other standard, but it
> might be useful. FreeBSD also made decision to import this function
> the libc.
There are at least 4 obvious problems with the proposed API:
1- How do you do error detection? Looks like you check for return
value of zero and a non-zero errno? This is bogus. It should return
0 on success and an error code on failure. The result should be
passed back by the caller providing a pointer.
2- It does not take a base argument.
3- It does not handle unsigned conversions. If we're going to keep
the same naming convention, it should be "strtoinum()" and "strtounum
()" (following strtoimax(3) and strotoumax(3)).
4- It should not produce "long long" results. It should produce a
"intmax_t" or "uintmax_t" (depending on if we're doing a signed or
Furthermore, the way that the error string is optionally returned is
not very internationalization-friendly. That whole error string
return should be disposed of. If the functionality is truly
desirable, then it should be an error sub-code to be interpreted by
> If there is some questions about this, to don't discuss it twice,
> checkout discussion in FreeBSD mailing list with OpenBSD folks:
> If there will be decision to import it, I attached patch and source
> manual, which goes to src/lib/libc/stdlib :) Please review.
> Best regards,