RE: import libraries for 3rd-party DLLs

RE: import libraries for 3rd-party DLLs

[Jim.Totten]

I am trying to use a third party msvc++ .lib file as well.  I was able
to create export and import files using the method mentioned often on
this list and in the users manual (nm followed by a dlltool) and my gcc
program seems to *link* without an errors - however when I execute the
program a window appears with the following message:

"The application or DLL is not a valid Windows NT image."

I saw in the archives someone else who got this same error message, but
there were no follow-ups to the post.  Anybody got some ideas about what
I could be doing wrong?

Thanks,

jt

	-----Original Message-----
	From:	Richard Hellicar (EML)
[SMTP:Rick.Hellicar@eml.ericsson.se]
	Sent:	Wednesday, March 10, 1999 10:39 AM
	To:	'cygwin@sourceware.cygnus.com'
	Subject:	import libraries for 3rd-party DLLs

	Hello,
	                                     
	                                                              
	I'm trying to create an "import library" to allow me to use gcc
with a
	third-party DLL.
	I tried the .lib files supplied with the DLL, but neither worked
(one was
	for MS, which
	did compile, but complained about entry points when executed,
the other for
	Borland).
	                                                              
	The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a
method in
	Chapter 4
	("Linking against DLLs").  However, if I run nm on *any* dll,
not just the
	one I'm trying
	to use, it tells me "No symbols in xyz.dll"

	In February, Gary Vaughan posted another method of producing
import
	libraries;
	you *can* produce a library in this way, but the linker chokes
on undefined
	references when you use it.

	Can of the cygwin gods tell me:
	1. Should I expect either the MS or Borland .lib files to be
compatible ?
	2. Is there a way of converting incompatible lib files ?
	3. Why doesn't nm find symbols in *any* DLL (try: for i in
	/winnt/system32/*.DLL; do nm $i; done)
	4. exactly what *is* supposed to be in a .def file; should the
@4,@8  stuff
	be in
	  there or not ?  Semi-colons ?

	I'm running cygwin B20.1 and  gcc version egcs-2.91.57 19980901

	Thanks in advance to you all


	Rick Hellicar
	-- 






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RE: import libraries for 3rd-party DLLs

[Jim.Totten]

I am trying to use a third party msvc++ .lib file as well.  I was able
to create export and import files using the method mentioned often on
this list and in the users manual (nm followed by a dlltool) and my gcc
program seems to *link* without an errors - however when I execute the
program a window appears with the following message:

"The application or DLL is not a valid Windows NT image."

I saw in the archives someone else who got this same error message, but
there were no follow-ups to the post.  Anybody got some ideas about what
I could be doing wrong?

Thanks,

jt

	-----Original Message-----
	From:	Richard Hellicar (EML)
[SMTP:Rick.Hellicar@eml.ericsson.se]
	Sent:	Wednesday, March 10, 1999 10:39 AM
	To:	'cygwin@sourceware.cygnus.com'
	Subject:	import libraries for 3rd-party DLLs

	Hello,
	                                     
	                                                              
	I'm trying to create an "import library" to allow me to use gcc
with a
	third-party DLL.
	I tried the .lib files supplied with the DLL, but neither worked
(one was
	for MS, which
	did compile, but complained about entry points when executed,
the other for
	Borland).
	                                                              
	The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a
method in
	Chapter 4
	("Linking against DLLs").  However, if I run nm on *any* dll,
not just the
	one I'm trying
	to use, it tells me "No symbols in xyz.dll"

	In February, Gary Vaughan posted another method of producing
import
	libraries;
	you *can* produce a library in this way, but the linker chokes
on undefined
	references when you use it.

	Can of the cygwin gods tell me:
	1. Should I expect either the MS or Borland .lib files to be
compatible ?
	2. Is there a way of converting incompatible lib files ?
	3. Why doesn't nm find symbols in *any* DLL (try: for i in
	/winnt/system32/*.DLL; do nm $i; done)
	4. exactly what *is* supposed to be in a .def file; should the
@4,@8  stuff
	be in
	  there or not ?  Semi-colons ?

	I'm running cygwin B20.1 and  gcc version egcs-2.91.57 19980901

	Thanks in advance to you all


	Rick Hellicar
	-- 






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import libraries for 3rd-party DLLs

[Richard Hellicar (EML)]

Hello,
                                     
                                                              
I'm trying to create an "import library" to allow me to use gcc with a
third-party DLL.
I tried the .lib files supplied with the DLL, but neither worked (one was
for MS, which
did compile, but complained about entry points when executed, the other for
Borland).
                                                              
The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a method in
Chapter 4
("Linking against DLLs").  However, if I run nm on *any* dll, not just the
one I'm trying
to use, it tells me "No symbols in xyz.dll"

In February, Gary Vaughan posted another method of producing import
libraries;
you *can* produce a library in this way, but the linker chokes on undefined
references when you use it.

Can of the cygwin gods tell me:
1. Should I expect either the MS or Borland .lib files to be compatible ?
2. Is there a way of converting incompatible lib files ?
3. Why doesn't nm find symbols in *any* DLL (try: for i in
/winnt/system32/*.DLL; do nm $i; done)
4. exactly what *is* supposed to be in a .def file; should the @4,@8  stuff
be in
  there or not ?  Semi-colons ?

I'm running cygwin B20.1 and  gcc version egcs-2.91.57 19980901

Thanks in advance to you all


Rick Hellicar
-- 






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Re: import libraries for 3rd-party DLLs

[Rik Hellicar]

Thanks to all for your replies. I'm now compiling, and linking and
running, but there're still some funnies.

Parameters I'm passing to functions in the DLL are getting broken on the
way.  Function calls which have no parameters work perfectly.  Return
values from function calls are fine too.

Any ideas ?  I know it works fine if I use Borland's bcc32, but that
particular compiler appears not to have setitimer and other such classics.



Regards,
-- 
Rick Hellicar



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Re: import libraries for 3rd-party DLLs

[Anders Norlander]

Richard Hellicar (EML) wrote:
> 
> Hello,
> 
> 
> I'm trying to create an "import library" to allow me to use gcc with a
> third-party DLL.
> I tried the .lib files supplied with the DLL, but neither worked (one was
> for MS, which
> did compile, but complained about entry points when executed, the other for
> Borland).
> 
> The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a method in
> Chapter 4
> ("Linking against DLLs").  However, if I run nm on *any* dll, not just the
> one I'm trying
> to use, it tells me "No symbols in xyz.dll"

The method suggested in the user's guide doesn't work if the
dll is stripped. (Hint: shouldn't this be mentioned in the ug?).
 
> 1. Should I expect either the MS or Borland .lib files to be compatible ?

Generally, no, and certainly not Borland lib files.
There are, however, patches to make gnu tools more MS compatible.

> 2. Is there a way of converting incompatible lib files ?

Depends on which format it is and if it is an import library
or a regular object library. At least in MSVC 6, I think MS
changed the format for import libraries and possibly other .lib
files as well. This stops the `nm ...' method of creating def
files from MS import libraries from working.

> 3. Why doesn't nm find symbols in *any* DLL (try: for i in
> /winnt/system32/*.DLL; do nm $i; done)
See above

> 4. exactly what *is* supposed to be in a .def file; should the @4,@8  stuff
> be in
>   there or not ?  Semi-colons ?

The @x are the total size of the parameters passed to a function using
the stdcall (standard win32) calling convention. Those functions are 
decorated that way by the compiler.
Semi-colons are comments.
 
Regards,
Anders

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Re: import libraries for 3rd-party DLLs

[Rik Hellicar]

Thanks to all for your replies. I'm now compiling, and linking and
running, but there're still some funnies.

Parameters I'm passing to functions in the DLL are getting broken on the
way.  Function calls which have no parameters work perfectly.  Return
values from function calls are fine too.

Any ideas ?  I know it works fine if I use Borland's bcc32, but that
particular compiler appears not to have setitimer and other such classics.



Regards,
-- 
Rick Hellicar



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Re: import libraries for 3rd-party DLLs

[Anders Norlander]

Richard Hellicar (EML) wrote:
> 
> Hello,
> 
> 
> I'm trying to create an "import library" to allow me to use gcc with a
> third-party DLL.
> I tried the .lib files supplied with the DLL, but neither worked (one was
> for MS, which
> did compile, but complained about entry points when executed, the other for
> Borland).
> 
> The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a method in
> Chapter 4
> ("Linking against DLLs").  However, if I run nm on *any* dll, not just the
> one I'm trying
> to use, it tells me "No symbols in xyz.dll"

The method suggested in the user's guide doesn't work if the
dll is stripped. (Hint: shouldn't this be mentioned in the ug?).
 
> 1. Should I expect either the MS or Borland .lib files to be compatible ?

Generally, no, and certainly not Borland lib files.
There are, however, patches to make gnu tools more MS compatible.

> 2. Is there a way of converting incompatible lib files ?

Depends on which format it is and if it is an import library
or a regular object library. At least in MSVC 6, I think MS
changed the format for import libraries and possibly other .lib
files as well. This stops the `nm ...' method of creating def
files from MS import libraries from working.

> 3. Why doesn't nm find symbols in *any* DLL (try: for i in
> /winnt/system32/*.DLL; do nm $i; done)
See above

> 4. exactly what *is* supposed to be in a .def file; should the @4,@8  stuff
> be in
>   there or not ?  Semi-colons ?

The @x are the total size of the parameters passed to a function using
the stdcall (standard win32) calling convention. Those functions are 
decorated that way by the compiler.
Semi-colons are comments.
 
Regards,
Anders

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import libraries for 3rd-party DLLs

[Richard Hellicar (EML)]

Hello,
                                     
                                                              
I'm trying to create an "import library" to allow me to use gcc with a
third-party DLL.
I tried the .lib files supplied with the DLL, but neither worked (one was
for MS, which
did compile, but complained about entry points when executed, the other for
Borland).
                                                              
The Cygwin User's Guide (Delorie, Humblet, Noer) suggests a method in
Chapter 4
("Linking against DLLs").  However, if I run nm on *any* dll, not just the
one I'm trying
to use, it tells me "No symbols in xyz.dll"

In February, Gary Vaughan posted another method of producing import
libraries;
you *can* produce a library in this way, but the linker chokes on undefined
references when you use it.

Can of the cygwin gods tell me:
1. Should I expect either the MS or Borland .lib files to be compatible ?
2. Is there a way of converting incompatible lib files ?
3. Why doesn't nm find symbols in *any* DLL (try: for i in
/winnt/system32/*.DLL; do nm $i; done)
4. exactly what *is* supposed to be in a .def file; should the @4,@8  stuff
be in
  there or not ?  Semi-colons ?

I'm running cygwin B20.1 and  gcc version egcs-2.91.57 19980901

Thanks in advance to you all


Rick Hellicar
-- 






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