Is this valid for printf (in MSVC)

[John E]

I'm trying to run a program that runs fine when built with gcc - and it builds okay with MSVC but crashes at run time.

I've traced the crash to a call to vsnprintf() which is getting passed a string like this:- "(Value: %s%s %+05.1lf dB) "

I've never seen %+05.1lf in a string before - is it a valid argument for MSVC?

[2kaud]

Yes. See:

int main() {
	printf("%+05.1lf\n", 1.456);
	printf("%+05.1lf\n", 123.456);
	printf("%+05.1lf\n", -13.456);
}

which displays:

+01.5
+123.5
-13.5

+ means displays + for +ve numb and - for -ve numb
0 means pad with 0
5.1 is width of 5 with 1 digit precision
lf means long double

[John E]

Thanks 2kaud - has it always been like that or is this something new - e.g. C17 or whatever ?

[2kaud]

It's always been like that except that "%lf" came with c99/C++11 when long double was introduced. Note that that MS VS double and long double are the same.

PS. Why are we both working on a Sunday morning ??

[John E]

Haha - quite right!

[John E]

Seems like this site's taken a backwards step again (believe it or not, it's only just notified me of 2kaud's replies from a fortnight ago !! )