I got a compilation error on Windows using Visual Studio 2013 (a.k.a. cl version 12.0), 64-bit, when building itk3.4.2.  The error was a redefined typedef:    typedef int ptrdiff_t;
I was able to work around the problem with this change:

$ diff -c ../devm3/prod/src/tcltk/8.6.x/tcl8.6.5/generic/tclInt.h prod/src/tcltk/8.6.x/tcl8.6.5/generic/tclInt.hprod/src/tcltk/8.6.x/tcl8.6.5/generic/tclInt.h          <
*** ../devm3/prod/src/tcltk/8.6.x/tcl8.6.5/generic/tclInt.h     2016-01-19 04:57:54.000000000 -0800
--- prod/src/tcltk/8.6.x/tcl8.6.5/generic/tclInt.h      2016-04-07 09:27:40.000000000 -0700
***************
*** 51,58 ****
--- 51,60 ----
  #ifdef STDC_HEADERS
  #include <stddef.h>
  #else
+ #ifndef _PTRDIFF_T_DEFINED
  typedef int ptrdiff_t;
  #endif
+ #endif


Really, "int" for a pointer diff type for a 64-bit build is the wrong size in general.

For me it compiles and runs well. Test caused ticket [db0a5f6417] ;-)

Thanks, Harald

Thanks, Harald!  Should really be fixed now in all branches.

> In which header file is ptrdiff_t typedef'd on MSVC6?

I made a grep-style search for "ptrdiff_t" on the MS-VC6 include folder

C:\Program Files (x86)\Microsoft Visual Studio\VC98\Include

There is one match: "STDDEF.H"

The snipped defining "ptrdiff_t" is as follows (line 84):

/* define the implementation dependent size types */

#ifndef _PTRDIFF_T_DEFINED
typedef int ptrdiff_t;
#define _PTRDIFF_T_DEFINED
#endif

Hope this helps, Harald

In which header file is ptrdiff_t typedef'd on MSVC6?

patthoyts	Hello. The commit recently for http://core.tcl.tk/tcl/info/e14c77b845 had introduced a problem when building with msvc6 on windows as crtdef.h doesn't exist.
patthoyts	If someone would like to poke the appropriate bug lists or whatever to get some fallthrough as suggested in the original bug submission it would be useful.
patthoyts	Of course, maybe you no longer support such ancient compilers.

patthoyts	For reference of build failure: https://jenkins.patthoyts.tk/job/TclKit/617/console
patthoyts	cheers all.

According to microsoft documentation, ptrdiff_t is supposed to be defined by crtdefs.h. Fixed in core-8-6-branch and trunk.

There exists a stddef.h file, but STDC_HEADERS is not defined.  Nor is __STDC__.  I speculate that since this is 64-bit Windows, the data/pointer model may not match standard C.

I changed the code to this and it seems to work:

#if defined(STDC_HEADERS) || defined(_WIN64)
#include <stddef.h>
#else
typedef int ptrdiff_t;
#endif

What do we know about the STDC_HEADERS value?  Is it
not getting set properly?

Is there really no <stddef.h> file at compile time?

Sorry, itcl, not itk:

        cl -nologo -c -W3 -YX -Fp.\Release_AMD64_VC12\itcl_Dynamic\ -Zi -Od -RTC1  -MD -I..\win -I..\generic -DBUILD_itcl -DTCL_THRE
ADS=1 -I"C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include" -DTCL_CFGVAL_ENCODING=\"cp1252\" -DTCL_CFG_OPTIMIZE
D -DUSE_TCL_STUBS -Fo.\Release_AMD64_VC12\itcl_Dynamic\ @C:\tmp\nm7FA1.tmp
cl : Command line warning D9002 : ignoring unknown option '-YX'
itcl_bicmds.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_class.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_cmds.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_ensemble.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_linkage.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_migrate.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_methods.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_objects.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_parse.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itcl_util.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
itclStubInit.c
C:\home\bgriffin\devmainwin\build\win64\tclcore86\opt\usr\include\tclInt.h(55) : error C2371: 'ptrdiff_t' : redefinition; diffe
rent basic types
        C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\INCLUDE\crtdefs.h(528) : see declaration of 'ptrdiff_t'
Generating Code...
NMAKE : fatal error U1077: 'C:\PROGRA~2\MICROS~3.0\VC\BIN\amd64\cl.EXE' : return code '0x2'
Stop.
make: *** [INCRTCL] Error 2