Trying to fix the following "macro redefinition" warning:
1>Path\to\MKL\include\math.h(1577): warning C4005: 'HUGE_VALF' : macro redefinition
1> Path\to\Microsoft Visual Studio 12.0\VC\include\../../vc/include/math.h(104) : see previous definition of 'HUGE_VALF'
Generated from this code:
#include "ABC/CUDA_FFT.h"
#include "ABC/logging.h"
#include "Utilities/Utils.h"
#pragma warning( push )
#pragma warning( disable : 4005 ) // macro redefinition (no effect)
#include <cufft.h>
#include <cuda_runtime.h>
#pragma warning( pop )
#include <complex>
The HUGE_VALF macro is defined in both included files.
I tried to #undef HUGE_VALF before including any of the above headers, but I still got the same warnings.
Since I have to use both Intel and Microsoft maths libraries, how can I prevent this warning from being generated?
If you really have to use two libraries with overlapping identifier names (poor you, I feel with you) then the only clean way is to use them from separated .c files.
I.e. make one .c file which includes the header for one lib and a second .c file which includes the header of the other lib.
Problems with overlapping macro definitions should be solved this way.
If you additionally have overlapping linker identifiers (function names, global variable names...), then it will be necessary to link the two code files separatly to the corresponding libs.
The real trouble starts if you then have to use functionalities from both libs in one function written by you. That will require to first wrap the two functionalities in uniquely named functions in the corresponding code files, which then can be unambigously called from another code file to use both.
Do not try to solve your problem with #undef, that is just a way to risk (or, according to murphy law, guarantee) that the wrong definition of overlapping macro names will be used unexpectedly.
In short, if you think that #undef could help you, then your problem is larger than you are aware of.
This might seem cynical, please understand that I only try to let you benefit from some serious scorch-mark experiences I made. Debugging in the presence of uncleanly overlapping symbols will get you singed. As I have mentioned in my profile, I learned to supersticiously consider #undef to be unlucky.
But, to also answer the actual question you wrote, to get rid of the "redefinition" symptom (not the problem, mind) you need to do the #undef BETWEEN the two includes, not before. That way the first include defines the problematic macro. Then it gets undefined. Then the second include defines it again, without seeing it already being defined.