gem install mongoid --platform=ruby failed to build gem native extension - ruby

Question

i 'm using windows 7 and when i try to install mongoid i have this problem this is the log
C:/Ruby200/bin/ruby.exe -r ./siteconf20140806-7376-tm3b3l.rb extconf.rb
creating Makefile
make "DESTDIR=" clean
make "DESTDIR="
generating native-i386-mingw32.def
compiling native.c
In file included from c:/Ruby200/include/ruby-2.0.0/ruby/defines.h:153:0,
from c:/Ruby200/include/ruby-2.0.0/ruby/ruby.h:70,
from c:/Ruby200/include/ruby-2.0.0/ruby.h:33,
from native.c:26:
c:/Ruby200/include/ruby-2.0.0/ruby/win32.h: In function 'rb_w32_pow':
c:/Ruby200/include/ruby-2.0.0/ruby/win32.h:801:5: warning: implicit declaration of
function '_controlfp' [-Wimplicit-function-declaration]
c:/Ruby200/include/ruby-2.0.0/ruby/win32.h:802:16: error: '_PC_64' undeclared (first
use in this function)
c:/Ruby200/include/ruby-2.0.0/ruby/win32.h:802:16: note: each undeclared identifier is
reported only once for each function it appears in c:/Ruby200/include/ruby-
2.0.0/ruby/win32.h:802:24: error: '_MCW_PC' undeclared (first use in this function)
make: *** [native.o] Error 1
make failed, exit code 2
i have installed devKit

Answer 1

I just had the same issues and this link https://github.com/mongoid/mongoid/issues/3489 helped me solve the problem.
So first, go to your ...\Ruby200\include\ruby-2.0.0\ruby directory and locate win32.h file.
Then modify the file by adding the missing variables:
...
...
static inline double
rb_w32_pow(double x, double y)
{
return powl(x, y);
}
#elif defined(__MINGW64_VERSION_MAJOR)
#ifndef _PC_64
#define _PC_64 0x00000000
#endif
#ifndef _MCW_PC
#define _MCW_PC 0x00030000
#endif
/*
* Set floating point precision for pow() of mingw-w64 x86.
* With default precision the result is not proper on WinXP.
*/
static inline double
rb_w32_pow(double x, double y)
{
double r;
unsigned int default_control = _controlfp(0, 0);
_controlfp(_PC_64, _MCW_PC);
r = pow(x, y);
/* Restore setting */
_controlfp(default_control, _MCW_PC);
return r;
}
...
...
Hope it works for you as well! Good luck!