IsNAN.cpp:23:3: #error "Don't know how to get isnan()"

Hi Brian

Here's the config.log (I'm not posting it on the dev-list).

The automatic gcc macro for Interix is __INTERIX if this is to any help.


config.log (87.7 KB)


I'm not exactly sure what's going on here. You mentioned in your
earlier message that isnan() is declared in <cmath>, but from looking
at your config.log, the check for isnan() in <cmath> that the
configure script runs appears to be failing. Can you check whether
either of the test programs actually compiles?

/* first test program: is isnan() declared in <cmath>? */
#include <cmath>
int foo(float f) {return isnan(f);}

/* second test program: is std::isnan() declared in <cmath>? */
#include <cmath>
using std::isnan;
int foo(float f) {return isnan(f);}

If not, perhaps there is a bug in the configure script's check. If
you can play around with one of the above test programs and get
make the int foo(float f) function to compile on Interix, let me
know how you did it, and I can fix the test.