Re: dlltool -N [PATCH]

["Aaron W. LaFramboise" <aaron98wiridge9 at aaronwl dot com>]

Shaun Jackman wrote:
> I'm using dlltool to create static library wrappers around
> pre-existing DLLs (such as coredll.dll and winsock.dll). The dllimport
> names, such as malloc, do not have an initial underscore. gcc, otoh,

No, the names in the .def don't, but dlltool adds one.  See below.

> expects malloc() to be called _malloc. So, -N adds an underscore to

Yes.  All regular C symbols on PECOFF 386 having a leading underscore in
the asm name (the low-level symbol name).  dlltool automatically adds a
single leading underscore to any symbol it creates to ensure proper C
linkage.

> the external symbol, but not the dllimport name.

This is a transcript from a terminal using vanilla release binutils 2.15
on i686-pc-mingw32:

$ cat elishacuthbert.def
LIBRARY elishacuthbert.dll
EXPORTS
gorgeous
$ dlltool -d elishacuthbert.def -l libelishacuthbert.a
$ objdump -t libelishacuthbert.a | grep gorgeous
[  7](sec  1)(fl 0x00)(ty   0)(scl   2) (nx 0) 0x00000000 _gorgeous
[  8](sec  5)(fl 0x00)(ty   0)(scl   2) (nx 0) 0x00000000 __imp__gorgeous
$

Notice that dlltool has already added a single leading underscore to the
imported external symbol asm name, as per the ABI.  (The other __imp__
name is the dllimport name.)

In other words, I don't see why -N would be necessary.  Are you saying
that you have some function with a C name of "_malloc" with an asm name
of "__malloc", that is called malloc in the .def file?  If so, I'd be
curious to know why its called _malloc instead of malloc, as it is named
in the .def file.

> I'm not familiar with --ext-prefix-alias. I didn't see any reference
> to it in dlltool(1). Is it a switch to another program?

It is in CVS, but not yet in any binutils release.  It adds aliases with
a specific external prefix to the external symbols in an import library.
 See http://sources.redhat.com/ml/binutils/2004-07/msg00130.html for
details.


Aaron W. LaFramboise