logf macro in math.h

[John E]

#include <math.h>

void SomeFunc()
{
      float_t winlen   = 4;
      float_t rayparam = 48./512. * winlen;

      float dfwvnorm = expf ( (logf(2.0)/rayparam) * (winlen+2) ); // <-- compiler error if I use 'logf' but not if I use 'log'
}

I'm trying to build libaubio using VC++8. There's a function that essentially boils down to the above, once I've allowed for a couple of #defines (EXP and LOG, respectively).

If I use (log(2.0)/rayparam) my compiler seems happy. But if I use (logf(2.0)/rayparam) (which was originally intended in the code) the compiler complains with error C2143: syntax error : missing ')' before ';'. And yet from looking at math.h, logf is defined everywhere that expf is defined. AFAICT they're defined as functions for 64-bit compiles and as macros for 32-bit (mine's 32-bit). Can anyone suggest a reason why the compiler is happy to accept the expf macro but not logf?


[Edit...] Amazingly, I've discovered a bug in math.h. the macro for logf incorrectly has a semicolon at the end - i.e

#define logf(x) ((float)log((double)(x)));

Currently I'm using VC2005 Professional but previously I'd been using VC2005 Express. I've just looked in the Express version's copy of math.h and that doesn't have the problem!

[ovidiucucu]

[Edit...] Amazingly, I've discovered a bug in math.h. the macro for logf incorrectly has a semicolon at the end - i.e

#define logf(x) ((float)log((double)(x)));

Currently I'm using VC2005 Professional but previously I'd been using VC2005 Express. I've just looked in the Express version's copy of math.h and that doesn't have the problem!

Hi John,
I have searched in all MATH.H from my computer (VC6.0/2005/2008/2010) and did not found any logf macro as you described.
Just

#define logf(x)     ((float)log((double)(x)))

with no semicolon.

Are you sure that yours isn't from onother third party library or was not modified by mistake?

[John E]

Invariably I add an annotation to a 3rd party file if I modify it so I don't think that's the problem. It's more likely that you've installed a service pack which I haven't got (in fact, I don't think I've installed any service packs at all yet for VS2005).

[ovidiucucu]

Indeed, I've installed service packs as well as SDK updates.
I will verify ASAP on a "clean" install.

[John E]

I have the Professional edition (on CD) and the Express edition which I downloaded. Only the Professional edition seems to have the problem. It has two copies of math.h (which strangely, aren't the same size) but both copies seem to be affected.

[Moschops]

Good spot; well done. Get the service pack to fix it.

http://connect.microsoft.com/VisualS...ling-semicolon

[ovidiucucu]

Well then, problem is solved.

[John E]

Must get around to installing that service pack..!