emacs-module is not GPL compatible (Windows)

emacs-module is not GPL compatible (Windows)

[Mambo Levis]

Hi,
I build the emacs-sqlite3 project in Windows using MINGW (mingw64_shell.bat) and the following message appears whenI requiere the module:
sqlite3-core.dll is not GPL compatible

Questions: 
1. Have anybody tried to build this project in windows using MINGW or Visual Studio?
2. Do you have any idea about the error message: sqlite3-core.dll is not GPL compatible?
I found this project (sqlite3-core) more interesting/valuable for testing the new emacs-module than the default provided (mod-test) in emacs-25.1-src/modules
Repository: https://github.com/syohex/emacs-sqlite3
I also found and build a similar project https://github.com/thom-jenks/emacs-sqlite but unfortunately with the same problem: it is not GPL compatible

Thanks
Levis

Re: emacs-module is not GPL compatible (Windows)

[Óscar Fuentes]

Mambo Levis <mambo.levis@gmail.com> writes:

First of all, please don't send usage questions to bug-gnu-emacs. That
list is for reporting defects, suggesting enhancements and submitting
patches.

> I build the emacs-sqlite3 project in Windows using MINGW
> (mingw64_shell.bat) and the following message appears whenI requiere
> the module: sqlite3-core.dll is not GPL compatible
>
> Questions: 
> 1. Have anybody tried to build this project in windows using MINGW or
> Visual Studio?

Which project?

> 2. Do you have any idea about the error message: sqlite3-core.dll is
> not GPL compatible?

Most likely the module does not define and export the symbol
plugin_is_GPL_compatible, as described here:

http://diobla.info/blog-archive/modules-tut.html#sec-2-2

> I found this project (sqlite3-core) more interesting/valuable for
> testing the new emacs-module than the default provided (mod-test) in
> emacs-25.1-src/modules
> Repository: https://github.com/syohex/emacs-sqlite3

Ah, *that* project :-)

> I also found and build a similar
> project https://github.com/thom-jenks/emacs-sqlite but unfortunately
> with the same problem: it is not GPL compatible

The problem is that the code does not export the symbol
plugin_is_GPL_compatible. On GNU/Linux symbols are exported by default
when you build the shared library, but that's not the case of Windows
where you must export them explicitly.

Try changing

int plugin_is_GPL_compatible;

to

__declspec(dllimport) int plugin_is_GPL_compatible;

Probably you will also need to change

int
emacs_module_init(struct emacs_runtime *ert)

to

int __declspec(dllimport)
emacs_module_init(struct emacs_runtime *ert)

Hope this helps.

Re: emacs-module is not GPL compatible (Windows)

[Óscar Fuentes]

Óscar Fuentes <ofv@wanadoo.es> writes:

> Try changing
>
> int plugin_is_GPL_compatible;
>
> to
>
> __declspec(dllimport) int plugin_is_GPL_compatible;
>
> Probably you will also need to change
>
> int
> emacs_module_init(struct emacs_runtime *ert)
>
> to
>
> int __declspec(dllimport)
> emacs_module_init(struct emacs_runtime *ert)

Sorry. I'm half-asleep. Please change the dllimport above with
dllexport.

bug#24574: emacs-module is not GPL compatible (Windows)

[Robert Cochran]

Mambo Levis <mambo.levis@gmail.com> writes:

> 2. Do you have any idea about the error message: sqlite3-core.dll is not GPL compatible?

Well, the library needs to provide a C symbol named
"plugin_is_GPL_compatible", which the first one does. So I'm not
entirely sure why Emacs is rejecting the library.

If I had to guess, I'd suppose that whatever compiler your using is
noticing that the symbol is never used and removes it. That's an
educated guess based on what I've seen compilers do for other things
that end up being unused; I have no idea if I'm anywhere close to
correct.

On that thought, though, perhaps you could modify the
`emacs_module_init` function to touch the variable (by doing something
like, say, 'plugin_is_GPL_compatible = 42') and see what happens?

HTH,
-- 
~Robert Cochran

GPG Fingerprint - E778 2DD4 FEA6 6A68 6F26  AD2D E5C3 EB36 4886 8871

bug#24574: emacs-module is not GPL compatible (Windows)

[Alain Schneble]

Mambo Levis <mambo.levis@gmail.com> writes:

> Hi,
> I build the emacs-sqlite3 project in Windows using MINGW (mingw64_shell.bat) and the following message appears whenI requiere the module:
> sqlite3-core.dll is not GPL compatible
>
> Questions: 
> 1. Have anybody tried to build this project in windows using MINGW or Visual Studio?
> 2. Do you have any idea about the error message: sqlite3-core.dll is not GPL compatible?
> I found this project (sqlite3-core) more interesting/valuable for testing the new emacs-module than the default provided (mod-test) in emacs-25.1-src/modules
> Repository: https://github.com/syohex/emacs-sqlite3
> I also found and build a similar project https://github.com/thom-jenks/emacs-sqlite but unfortunately with the same problem: it is not GPL compatible
>
> Thanks
> Levis

FWIW, mod-test works properly here on mingw64 with gcc 6.1.0, even with
CFLAGS='-O3'.  Did you try with mod-test?  Do you get the same error?

Alain

Re: emacs-module is not GPL compatible (Windows)

[Mambo Levis]

Yes, I tried mod-test and it worked properly without using any calling convention such __declspec(dllexport).
I have made the following tests:
1. I commented all module's functions related with sqlite3 library and only leave uncommented one of function to verify if the module is working:
  /* emacs-sqlite-version*/static emacs_valueFemacs_sqlite_version (emacs_env *env, ptrdiff_t nargs, emacs_value args[], void *data){     const char* msg_docstr = "emacs-sqlite module version 0.1";  return env->make_string (env, msg_docstr, strlen(msg_docstr));}
When I require (emacs-sqlite-version) it works as expected.
2. I tested only two function: the previous one Femacs_sqlite_version and other associated with sqlite. Once I consider a module function related to sqlite error message appears: is not GPL compatible

I think the error is related with the linking process of the sqlite3.lib . One possible test is not linking sqlite3.lib and stead just using sqlite source code as a part of the module.
Do you have any suggestion?
Levis

 

    On Saturday, October 1, 2016 9:54 AM, Alain Schneble <a.s@realize.ch> wrote:
 

 Mambo Levis <mambo.levis@gmail.com> writes:

> Hi,
> I build the emacs-sqlite3 project in Windows using MINGW (mingw64_shell.bat) and the following message appears whenI requiere the module:
> sqlite3-core.dll is not GPL compatible
>
> Questions: 
> 1. Have anybody tried to build this project in windows using MINGW or Visual Studio?
> 2. Do you have any idea about the error message: sqlite3-core.dll is not GPL compatible?
> I found this project (sqlite3-core) more interesting/valuable for testing the new emacs-module than the default provided (mod-test) in emacs-25.1-src/modules
> Repository: https://github.com/syohex/emacs-sqlite3
> I also found and build a similar project https://github.com/thom-jenks/emacs-sqlite but unfortunately with the same problem: it is not GPL compatible
>
> Thanks
> Levis

FWIW, mod-test works properly here on mingw64 with gcc 6.1.0, even with
CFLAGS='-O3'.  Did you try with mod-test?  Do you get the same error?

Alain


   

bug#24574: emacs-module is not GPL compatible (Windows)

[Eli Zaretskii]

[Please don't cross post to help-gnu-emacs if you report bugs.]

> Date: Sat, 1 Oct 2016 12:31:26 +0000 (UTC)
> From: Mambo Levis <mambo.levis@gmail.com>
> Cc: 24574@debbugs.gnu.org, help-gnu-emacs@gnu.org
> 
> 1. I commented all module's functions related with sqlite3 library and only leave uncommented one of function
> to verify if the module is working:
> 
> /* emacs-sqlite-version*/
> static emacs_value
> Femacs_sqlite_version (emacs_env *env, ptrdiff_t nargs, emacs_value args[], void *data)
> {
> const char* msg_docstr = "emacs-sqlite module version 0.1";
> return env->make_string (env, msg_docstr, strlen(msg_docstr));
> }
> 
> When I require (emacs-sqlite-version) it works as expected.
> 
> 2. I tested only two function: the previous one Femacs_sqlite_version and other associated with sqlite. Once I
> consider a module function related to sqlite error message appears: 
> is not GPL compatible
> 
> I think the error is related with the linking process of the sqlite3.lib . One possible test is not linking sqlite3.lib
> and stead just using sqlite source code as a part of the module.
> 
> Do you have any suggestion?

I'd start by using the pexports program (or something similar) to see
which symbols are exported by the sqlite DLL.

bug#24574: emacs-module is not GPL compatible (Windows)

[Mambo Levis]

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Thank you for the pexports recommendation.
For somebody that just read this problem for the first time, a summary:
Emacs version: GNU Emacs 25.1.1

Emacs module repo: https://github.com/syohex/emacs-sqlite3

Build process: mingw64_shell.bat (Windows) 
Dependency: sqlite.lib
Makefile:
EMACS = D:\user\emacs-src\emacs-25-branch-srcINCLUDE = -I. -I$(EMACS)\src 
CC      = gccLD      = gccLDFLAGS =
# On MS-Windows, say "make SO=dll" to build the moduleSO      = dll# -fPIC is a no-op on Windows, but causes a compiler warningifeq ($(SO),dll)CFLAGS  = -std=gnu99 -ggdb3 -WallelseCFLAGS  = -std=gnu99 -ggdb3 -Wall -fPICendif
all: sqlite3-core.$(SO)
%.$(SO): %.o $(LD) -shared $(LDFLAGS) -o $@ $< sqlite3.lib
%.o: %.c $(CC) $(CFLAGS) $(INCLUDE) -c $<
check: $(EMACS)/src/emacs -batch -l ert -l test.el -f ert-run-tests-batch-and-exit    clean: rm -rf *.o *.dll *.a *.d
--------------------------------------------------------------------------------------------------------------------------------
Now the result of my tests:

1. The symbols exported by the modules without considering any sqlite function are:
 LIBRARY sqlite3-core.dll
EXPORTSemacs_module_init ; .text ; RVA 00001685plugin_is_GPL_compatible DATA ; no section ; RVA 00007010
2. onsidering the following sqlite3 related function:
static voidel_sqlite3_free(void *arg){ sqlite3_close((sqlite3*)arg);}
When I generate the sqlite3-core.dll using at least one sqlite3 DLL function, for example sqlite3_close , an error message appears:  (the module can't be found) ..../modules/emacs-sqlite3/sqlite3-core.dll: Das angegebene Modul wurde nicht gefunden.

I check the sqlite3.dll using pexports tool, and the symbols sqlite3_close is exported.LIBRARY sqlite3.dllEXPORTS.....sqlite3_changes ; .text ; RVA 0009c648sqlite3_clear_bindings ; .text ; RVA 000373dcsqlite3_close ; .text ; RVA 0009c9e8sqlite3_close_v2 ; .text ; RVA 0009ca08sqlite3_collation_needed ; .text ; RVA 0009f4b3sqlite3_collation_needed16 ; .text ; RVA 0009f51f
I check the module qlite3-core.dll again and the symbols are there.
; .text   : RVA: 00001000, File offset: 00000600; .data   : RVA: 00003000, File offset: 00002400; .rdata  : RVA: 00004000, File offset: 00002600; .pdata  : RVA: 00005000, File offset: 00002e00; .xdata  : RVA: 00006000, File offset: 00003200; .bss    : RVA: 00007000, File offset: 00000000; .edata  : RVA: 00008000, File offset: 00003400; .idata  : RVA: 00009000, File offset: 00003600; .CRT    : RVA: 0000a000, File offset: 00003e00; .tls    : RVA: 0000b000, File offset: 00004000; .reloc  : RVA: 0000c000, File offset: 00004200; /4      : RVA: 0000d000, File offset: 00004400; /19     : RVA: 0000e000, File offset: 00004800; /31     : RVA: 00018000, File offset: 0000e200; /45     : RVA: 0001a000, File offset: 0000fa00; /57     : RVA: 0001c000, File offset: 00011200; /70     : RVA: 0001d000, File offset: 00011e00; /81     : RVA: 0001e000, File offset: 00012200; /92     : RVA: 00021000, File offset: 00015200; /105    : RVA: 0002b000, File offset: 0001f200; Reading exports from section: .edata; Export table: sqlite3-core.dll; Ordinal base: 1; Ordinal table RVA: 00008038; Name table RVA: 0008030; Export address table RVA: 00008028LIBRARY sqlite3-core.dllEXPORTSemacs_module_init ; .text ; RVA 00001696plugin_is_GPL_compatible DATA ; no section ; RVA 000078f0 

Please, notice that this time the plugin_is_GPL_compatible. The problem is now that the module can't be found when a sqlite3.dll symbol is used.
Any Idea or suggestion?
Thanks
Levis
    On Saturday, October 1, 2016 5:40 PM, Eli Zaretskii <eliz@gnu.org> wrote:
 

 [Please don't cross post to help-gnu-emacs if you report bugs.]

> Date: Sat, 1 Oct 2016 12:31:26 +0000 (UTC)
> From: Mambo Levis <mambo.levis@gmail.com>
> Cc: 24574@debbugs.gnu.org, help-gnu-emacs@gnu.org
> 
> 1. I commented all module's functions related with sqlite3 library and only leave uncommented one of function
> to verify if the module is working:
> 
> /* emacs-sqlite-version*/
> static emacs_value
> Femacs_sqlite_version (emacs_env *env, ptrdiff_t nargs, emacs_value args[], void *data)
> {
> const char* msg_docstr = "emacs-sqlite module version 0.1";
> return env->make_string (env, msg_docstr, strlen(msg_docstr));
> }
> 
> When I require (emacs-sqlite-version) it works as expected.
> 
> 2. I tested only two function: the previous one Femacs_sqlite_version and other associated with sqlite. Once I
> consider a module function related to sqlite error message appears: 
> is not GPL compatible
> 
> I think the error is related with the linking process of the sqlite3.lib . One possible test is not linking sqlite3.lib
> and stead just using sqlite source code as a part of the module.
> 
> Do you have any suggestion?

I'd start by using the pexports program (or something similar) to see
which symbols are exported by the sqlite DLL.


   

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bug#24574: emacs-module is not GPL compatible (Windows)

[Eli Zaretskii]

> Date: Sat, 1 Oct 2016 20:28:15 +0000 (UTC)
> From: Mambo Levis <mambo.levis@gmail.com>
> Cc: "a.s@realize.ch" <a.s@realize.ch>, 
> 	"24574@debbugs.gnu.org" <24574@debbugs.gnu.org>
> 
> %.$(SO): %.o
> $(LD) -shared $(LDFLAGS) -o $@ $< sqlite3.lib
> [...]
> Please, notice that this time the plugin_is_GPL_compatible. The problem is now that the module can't be
> found when a sqlite3.dll symbol is used.
> 
> Any Idea or suggestion?

Add -Wl,-export-all-symbols to LDFLAGS.

bug#24574: emacs-module is not GPL compatible (Windows)

[Mambo Levis]

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Hi,
I found the problem:
I checked everything again using the tool pexports, and both sqlite3-core.dll and sqlite3.dll were exporting all symbols. I compare all with the following article:http://gernotklingler.com/blog/creating-using-shared-libraries-different-compilers-different-operating-systems/  and I couldn't find any problem. 


The only thing left to do was to put sqlite.dll in the emacs\bin folder and Voilà, now it works. In fact I had already added the path and used  to sqlite3.dll in my emacs init file, but the location was wrong; after my emacs-modules collection. 
Thank you for your feedback and support. 
Muchas gracias Oscar Fuentes por tu colaboración.
Levis


 

    On Sunday, October 2, 2016 8:24 AM, Eli Zaretskii <eliz@gnu.org> wrote:
 

 > Date: Sat, 1 Oct 2016 20:28:15 +0000 (UTC)
> From: Mambo Levis <mambo.levis@gmail.com>
> Cc: "a.s@realize.ch" <a.s@realize.ch>, 
>     "24574@debbugs.gnu.org" <24574@debbugs.gnu.org>
> 
> %.$(SO): %.o
> $(LD) -shared $(LDFLAGS) -o $@ $< sqlite3.lib
> [...]
> Please, notice that this time the plugin_is_GPL_compatible. The problem is now that the module can't be
> found when a sqlite3.dll symbol is used.
> 
> Any Idea or suggestion?

Add -Wl,-export-all-symbols to LDFLAGS.


   

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bug#24574: emacs-module is not GPL compatible (Windows)

[npostavs]

Mambo Levis <mambo.levis@gmail.com> writes:

> Please, notice that this time the plugin_is_GPL_compatible. The
> problem is now that the module can't be found when a sqlite3.dll
> symbol is used.

What was the difference between this time and the previous time?

>
> The only thing left to do was to put sqlite.dll in the emacs\bin
> folder and Voilà, now it works. In fact I had already added the path
> and used to sqlite3.dll in my emacs init file, but the location was
> wrong; after my emacs-modules collection.

So there is no bug after all?  Should we just close this report, or is
there perhaps some guidance we should add to the documentation about how
to build modules on Windows?

bug#24574: emacs-module is not GPL compatible (Windows)

[Mambo Levis]

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Hi,
Yes, in summary there is no bug after all, yes you can close it.
Recommendations for windows users:

Problem 1: "The module is not GPL compatible". My suggestion is to provide a more generic Makefile able to link external libraries such Sqlite. Attached you can find the final version of the Makefile I used to build the module. Another recommendation is to test if DLL symbols are exported using tools such pexports or Dependecy walker. 
Problem 2: "The emacs module can't be found". This is easy to handle by adding the path to sqlite3.dll to windows environment variables. Other solution is put the sqlite3.dll in the same folder where the emacs.exe is located. In case that someone add the path to sqlite3.dll in emacs init file, it should be located before calling the emacs module. In my case, I move my windows path setup in emacsto the top of the init file.
I think the most important was the support I receive from you, thank you.
Levis

 

    On Wednesday, October 5, 2016 4:48 AM, "npostavs@users.sourceforge.net" <npostavs@users.sourceforge.net> wrote:
 

 Mambo Levis <mambo.levis@gmail.com> writes:

> Please, notice that this time the plugin_is_GPL_compatible. The
> problem is now that the module can't be found when a sqlite3.dll
> symbol is used.

What was the difference between this time and the previous time?

>
> The only thing left to do was to put sqlite.dll in the emacs\bin
> folder and Voilà, now it works. In fact I had already added the path
> and used to sqlite3.dll in my emacs init file, but the location was
> wrong; after my emacs-modules collection.

So there is no bug after all?  Should we just close this report, or is
there perhaps some guidance we should add to the documentation about how
to build modules on Windows?

   

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# Makefile V3

# Test GNU Emacs modules.

# Copyright 2015-2016 Free Software Foundation, Inc.

# This file is part of GNU Emacs.

# GNU Emacs is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# GNU Emacs is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

EMACS = D:\user\emacs-src\emacs-25-branch-src
INCLUDE = -I. -I$(CURDIR)\src -I$(EMACS)\src -I$(CURDIR)\lib
LIB = $(CURDIR)\lib

CC      = gcc
LD      = gcc
LDFLAGS = 

# On MS-Windows, say "make SO=dll" to build the module
SO      = dll
# -fPIC is a no-op on Windows, but causes a compiler warning
ifeq ($(SO),dll)
CFLAGS  = -std=gnu99 -ggdb3 
else
CFLAGS  = -std=gnu99 -ggdb3 -fPIC
endif

all: sqlite3-core.$(SO)

%.$(SO): %.o
	$(LD) -shared $(LDFLAGS) -o $@ $< $(LIB)\sqlite3.lib

%.o: %.c
	$(CC) $(CFLAGS) $(INCLUDE) -c $<

check:
	$(EMACS)/src/emacs -batch -l ert -l test.el -f ert-run-tests-batch-and-exit
    
clean:
	rm -rf *.o *.dll *.a *.d

bug#24574: emacs-module is not GPL compatible (Windows)

[Stefan Kangas]

Mambo Levis <mambo.levis@gmail.com> writes:

> On Wednesday, October 5, 2016 4:48 AM, "npostavs@users.sourceforge.net" <npostavs@users.sourceforge.net> wrote:
[...]
>> So there is no bug after all?  Should we just close this report, or is
>> there perhaps some guidance we should add to the documentation about how
>> to build modules on Windows?
[...]
> Yes, in summary there is no bug after all, yes you can close it.

Thanks, I read this thread and I can't see what we can add here besides
the usual "fiddle with paths, put stuff where it belongs".

So I'm closing this bug report.