(from "Extended keywords" in Watcom cuserguide.pdf)

__stdcall (32-bit only) The stdcall keyword may be used with function definitions,
and indicates that the 32-bit Win32 calling convention is to be used.
Notes:

(OK) 1. All symbols are preceded by an underscore character.

2. All C symbols (extern "C" symbols in C++) are suffixed by "@nnn"
where "nnn" is the sum of the argument sizes (each size is rounded up
to a multiple of 4 bytes so that char and short are size 4). When the
argument list contains "...", the "@nnn" suffix is omitted.

(OK) 3. Arguments are pushed on the stack from right to left. That is, the last
argument is pushed first. The called routine will remove the
arguments from the stack.

4. When a structure is returned, the caller allocates space on the stack.
The address of the allocated space will be pushed on the stack
immediately before the call instruction. Upon returning from the call,
register EAX will contain address of the space allocated for the return
value. Floating-point values are returned in 80x87 register ST(0).

5. Registers EAX, ECX and EDX are not saved and restored when a call
is made.
