From: Shan-leung Maverick WOO <maverick@...>
Date: 2001-06-23T02:42:42+09:00
Subject: [ruby-talk:16777] mkexports.rb and VC6SP5

Hello,

For some reason my VC6 (SP5, running on Win2k) generate object files with
symbols mangled with two under-scores:

> File miniruby.map:
>  0002:00000020       __real@40f0000000000000    004b0020     bignum.obj
>  0002:00000030       __real@41cfffffff800000    004b0030     bignum.obj
>  0002:00000040       __real@0000000000000000    004b0040     bignum.obj
>  0002:00000050       __real@40efffe000000000    004b0050     bignum.obj
>  0002:00000060       __real@412e848000000000    004b0060     eval.obj
>  0002:00000070       __real@46293e5939a08cea    004b0070     eval.obj
>  0002:00000080       __real@3eb0c6f7a0b5ed8d    004b0080     eval.obj
>  0002:00000090       __real@3faeb851eb851eb8    004b0090     eval.obj
>  0002:000000a0       __real@4010000000000000    004b00a0     math.obj
>  0002:000000b0       __real@3ff0000000000000    004b00b0     math.obj
>  0002:000000c0       __real@c1e0000000000000    004b00c0     numeric.obj
>  0002:000000d0       __real@41dfffffffc00000    004b00d0     numeric.obj
>  0002:000000e0       __real@c1d0000000000000    004b00e0     numeric.obj
>  0002:000000f0       __real@3fe0000000000000    004b00f0     numeric.obj
>  0002:00000100       __real@40e0000000000000    004b0100     random.obj
>  0002:00000718       __real@408f400000000000    004b0718     time.obj

However, mkexports.rb will cut the first under-score off to generate the def
file. This works in the normal case when symbols are mangled with one
under-score in the front, but not in the __ case.

I searched the archive and three articles shows up: 9226, 9138 and 9264. The
solution there seems to suggest that I should remove those offending
declarations in the def file. I think that will work, but changing
mkexports.rb may be a better solution:

C:\ruby-1.6.4\win32>diff mkexports.rb mkexports.rb.old
9c9
<   if l.sub!(/^_([^_])/, '\1')
---
>   if l.sub!(/^_/, '')

Actually I have no time to dig out why VC will do this kind of mangling.
(Any one have clues?) But for the moment I think this patch is worth putting
into later Ruby distributions.

Cheers!

-- 
All the best,
Maverick Woo

P.S. For the record, my other Win2k machine running VC6 SP4 does not
generate this kind of __-mangled symbols.