[Mesa-dev] [PATCH 02/10] mesa: remove M_PI, M_E, M_LOG2E macro definitions

[Jose Fonseca]

On 26/02/15 09:19, Erik Faye-Lund wrote:
> On Thu, Feb 26, 2015 at 10:10 AM, Erik Faye-Lund <kusmabite at gmail.com> wrote:
>> On Thu, Feb 26, 2015 at 4:24 AM, Matt Turner <mattst88 at gmail.com> wrote:
>>> On Wed, Feb 25, 2015 at 5:29 PM, Brian Paul <brianp at vmware.com> wrote:
>>>> Should be defined in math.h.  If not, we can add them to c99_math.h
>>>
>>> And FWIW, the MSDN page [0] says that if you define _USE_MATH_DEFINES
>>> before including math.h, these will be defined for you. Not sure what
>>> versions of MSVC that applies to.
>>>
>>> [0] https://urldefense.proofpoint.com/v2/url?u=https-3A__msdn.microsoft.com_en-2Dus_library_4hwaceh6.aspx&d=AwIGaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=zfmBZnnVGHeYde45pMKNnVyzeaZbdIqVLprmZCM2zzE&m=X_K0Nwx5tQCSFwVyG_ZygN6O81dMZbappObbbXBIo8o&s=RfLpDMUnAlzskfxAQZy8epMADQIMRc0BG2CFhhdtLlM&e=
>>
>> That link says "Visual Studio 2013", but roughly the same message is
>> also in the Visual Studio .NET 2003 docs (available through the "Other
>> Versions"-selector at the top).
>>
>> IIRC, this has been the case since VC6, but we probably don't care
>> about that old toolchains.
>
> By the way, it seems we already define _USE_MATH_DEFINES, at least here:
>
> https://urldefense.proofpoint.com/v2/url?u=http-3A__cgit.freedesktop.org_mesa_mesa_tree_scons_gallium.py-3Fid-3D9db7b12cb283b915865d99d2fd3356af0662a18e-23n328&d=AwIGaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=zfmBZnnVGHeYde45pMKNnVyzeaZbdIqVLprmZCM2zzE&m=X_K0Nwx5tQCSFwVyG_ZygN6O81dMZbappObbbXBIo8o&s=wyVfp2Vd2fgWXHkzZhXPVVcPSuCIGZvTEJAzvQgunLI&e=
>
> But do we always build for MSVC with SCons, and with gallium? If so,
> it seems this patch is OK from a MSVC's point of view.

That's right.  _USE_MATH_DEFINES should be always defined on MSVC.

We could add

   #if defined(_MSC_VER) && !defined(_USE_MATH_DEFINES)
   #error _USE_MATH_DEFINES define required when building with MSVC
   #endif

To make this explicit.  Actually defining _USE_MATH_DEFINES in the 
headers is hopeless, because the .c file might have included math.h 
before, so it can be too late.  It must be passed to cl.exe to be 100% sure.

Jose