Using C preprocessor to construct a string literal for scanf?

Posted by Brett on Stack Overflow See other posts from Stack Overflow or by Brett
Published on 2010-04-29T19:05:37Z Indexed on 2010/04/29 19:07 UTC
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I'm attempting to create an sscanf string literal to aid in buffer overrun prevention in C99. The goal is something like:

#define MAX_ARG_LEN   16

char arg[MAX_ARG_LEN] = "";

if (sscanf(arg, "%"(MAX_ARG_LEN-1)"X", &input) > 0)

The obvious "manual" solution is something like:

#define MAX_ARG_LEN   16
#define MAX_ARG_CHARS "15"

char arg[MAX_ARG_LEN] = "";

if (sscanf(arg, "%"MAX_ARG_CHARS"X", &input) > 0)

However, I would prefer something to automatically generate "%15X" given a buffer size of 16. This link is almost works for my application: http://stackoverflow.com/questions/240353/convert-a-preprocessor-token-to-a-string but it does not handle the -1.

Suggestions?

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Using C preprocessor to construct a string literal for scanf? - Developer IT

Using C preprocessor to construct a string literal for scanf?

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