Gambit is generating some warnings under Windows. Some of them look like real errors:

1 d:\tools\Scheme\proj\gambc40b13\lib\os_tty.c(7344) : warning C4113: 'BOOL (__stdcall *)()' differs in parameter lists from 'PHANDLER_ROUTINE' 2 d:\tools\Scheme\proj\gambc40b13\lib\os_tty.c(7362) : warning C4113: 'BOOL (__stdcall *)()' differs in parameter lists from 'PHANDLER_ROUTINE' 3 d:\tools\Scheme\proj\gambc40b13\lib\os_time.c(234) : warning C4307: '*' : integral constant overflow 4 d:\tools\Scheme\proj\gambc40b13\lib\os_time.c(234) : warning C4244: 'initializing' : conversion from 'LONGLONG' to 'int', possible loss of data 5 d:\tools\Scheme\proj\gambc40b13\lib\os_time.c(235) : warning C4244: 'initializing' : conversion from 'LONGLONG' to 'int', possible loss of data 6 d:\tools\Scheme\proj\gambc40b13\lib\os_time.c(1316) : warning C4113: 'DWORD (__stdcall *)()' differs in parameter lists from 'LPTHREAD_START_ROUTINE' 7 d:\tools\Scheme\proj\gambc40b13\lib\os_shell.c(177) : warning C4244: '=' : conversion from 'unsigned short' to 'char', possible loss of data 8 d:\tools\Scheme\proj\gambc40b13\lib\os_shell.c(444) : warning C4244: '=' : conversion from 'unsigned short' to 'char', possible loss of data 9 d:\tools\Scheme\proj\gambc40b13\lib\os_shell.c(466) : warning C4244: '=' : conversion from 'unsigned short' to 'char', possible loss of data 10 d:\tools\Scheme\proj\gambc40b13\lib\os_shell.c(594) : warning C4244: '=' : conversion from 'unsigned short' to 'char', possible loss of data 11 d:\tools\scheme\proj\gambc40b13\lib\os_io.c(5527) : warning C4700: local variable 'dev' used without having been initialized

There are two other warnings that appear about 200 times building the library. I presume they're intentional:

12 d:\tools\Scheme\proj\gambc40b13\lib_std.c(2011) : warning C4146: unary minus operator applied to unsigned type, result still unsigned 13 d:\tools\Scheme\proj\gambc40b13\lib_std.c(21221) : warning C4244: '=' : conversion from 'double' to 'float', possible loss of data

Here's an example of the first:

___BIGFIX1(-0x80000000L)

Here's an example of the second:

___F32VECTORSET(___R1,___R3,___F64V1)

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Problems 1, 2, and 6 are happening because __STDC__ isn't defined by default under MSVC. MS thinks that because they define various extensions they aren't strict ANSI C, so by default they define _MSC_EXTENSIONS instead. Here are the relevant bits from the docs:

__STDC__ Indicates full conformance with the ANSI C standard. Defined as the integer constant 1 only if the /Za compiler option is given and you are not compiling C++ code; otherwise is undefined.

_MSC_EXTENSIONS This macro is defined when compiling with the /Ze compiler option (the default). Its value, when defined, is 1.

Because of all of the above, __P falls through to the #else at 1150 in gambit.h and treats params as K&R, which is wrong.

The problem can be fixed by either looking specifically for something like _MFC_VER or _MSC_EXTENSIONS or by forcing a #define of __STDC__. (I took the second route in my project file.)

Problem 11 looks legit.

(The problem with ___REGISTER_HOST_ENTRY was described elsewhere.)