Windows, MinGW. go1 and tip.

When using cgo to call a __stdcall decorated function that is dynamically imported,
cmd/ld gives a "funcname(0): not defined" message. This happens because the
import name is decorated with the argument size (funcname@0).

So the dynimport looks like:
#pragma dynimport funcname@0 funcname@0 libname.dll

The first issue is that it, from my understanding, it should look like:
#pragma dynimport funcname funcname@0 libname.dll

The second issue is that cgo uses the @ character here for symbol versioning in ELF, and
the decorator gets stripped from the symbol.

I have attached a .zip file with a minimal library and a .go file to reproduce this.
Just extract somewhere in $GOPATH/src and run make.bat, as long as you have MinGW setup.

I do believe a probable fix would be simple. The symbol version delimiter would be
changed to a '#' or another character, and the decorator for imported symbols in pe
objects for the first dynimport argument would be stripped. I will put together a CL for
review sometime soon. Initial testing of this seems to be promising, but my
understanding of how cgo, ld, etc. works is limited so I could definitely be doing this
wrong.

Discussion: https://groups.google.com/d/topic/golang-dev/Lf1H_3jbQgw/discussion

Attachments:

1. cgostdcall.zip (1316 bytes)