Talking about scanf

[fisher at sc2a.unige.ch]

In article <960 at mwtech.UUCP>, martin at mwtech.UUCP (Martin Weitzel) writes:
> [...]
> BTW: Recently there occured a problem, to which I couldn't find an
> immediate solution. Take the following program fragment:
> 
> 	#define X 100
> 	char word[X+1]; int z;
> 
> 	scanf("%100[^:]:%d", word, &z);
> 	        ^^^----------------------- I'd rather want X here; still
> 	           better were `(sizeof word) - 1', so that I could ommit
> 	           the #define for X completly

Yeah, it would be nice if we could have a `scanf("%*s", sizeof(word), word)'
printf-like type of construct, but then the `*' is already used for something
else...

As another workaround, it seems that some compilers *do* expand macros inside
strings and character constants, in which case you could use the `X' there.
If not, try to look in the the `Token Replacement' chapter of your compiler's
`User Guide'.  In TC, for example, you can "stringize" a macro, with the `#'
symbol (i.e. `#X' is converted to `"100"').  Another feature of TC is the
automatic concatenation of string literals (i.e. `"hello " "world"' becomes
`"hello world"').  With these features, you can rewrite your example as

	scanf("%" #X "[^:]:%d", word, &z);

Not really portable, you this can be useful.

Markus Fischer, Dpt of Anthropology, Geneva.