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Re: strtonum(3) from OpenBSD?

On Mon, Jun 29, 2009 at 11:41:04PM -0400, James K. Lowden wrote:
> I fail to see how sscanf(3) is more error prone than strtonum().  No
> matter what, you have to specify -- via the name or the format string --
> the format of the input and of the receiving buffer.  At least with
> sscanf(3) that's *all* you have to do.

Correct use of sscanf() for a single integer is something like:

        count = sscanf(inbuf, "%i%n", &int_val, &byte_count);
        if (count != 2 || inbuf[byte_count] != 0)
                /* Conversion error */

I'm not sure that it is possible to detect numeric overflow.

If you start using more complicated format strings, then you have to
be even more careful that the user-supplied input is correctly processed.


David Laight:

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