msvcrt: portable printf integer conversions

Mike McCormack mike at
Mon Sep 26 23:02:14 CDT 2005

Jesse Allen wrote:

> I've read various printf implementation over time.  The last one,
> ReactOS, seemed to provide support for numbering systems base 2
> through 36.  You'll see my version does mimic theirs, but we never do
> anything other than 8, 10, and 16.  I'm not sure if there is any
> printf out there that actually allows you to specify the base.  For
> this patch it could easily be cut to the 'f' as maximum, except I use
> the 'x' digit in the case of the special 0x and 0X prepending cases. 
> To change that, we just add in a test for the large type there.

Generally if something isn't used, then it shouldn't be included.  You 
specified your 'x' as digits[33], and you could easily delete the rest 
of the alphabet after 'f' and use digits[16] for 'x'.

> I will pull up my patch of test cases (never applied) from last time
> and see if it will still work against cvs.

Somebody (not you, i think) submitted a few test cases before that did 
something like:

printf(buf,"%s %d %c\n", "blah", 10, 'x' );
ok( strlen(buf) == 9, "wrong length\n" );

That doesn't test the code so well, so please make sure to check the 
output is correct in an unambiguous way. eg.

ok( !strcmp(buf,"blah 10 x"), "wrong output\n");

I'd check some combinations of stuff like:

( %I64x %0I64x %1I64d %i64x %i64d %I64D %50I64d %-1I64d %-50I64d etc )
for values: 0, -1, ~1, ~0, 100, -100


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