First Module: Not recognized by VLC

[Lehm]

Greetings! I am working on my first module for VLC as a side project. I'm normally a Visual Studio developer and not at all used to using make files to cross compile on linux. However I managed to muddle my way through the tutorials and can successfully compile (out of tree) a very basic useless module. However when I attempt to use it on the Windows version it doesn't appear in the list of recognized modules.

The steps I took:

Code:

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#include <vlc_common.h> #include <vlc_plugin.h> #define DOMAIN "vlc-myplugin" #define _(str) dgettext(DOMAIN, str) #define N_(str) (str) static int Open(vlc_object_t *); static void Close(vlc_object_t *); vlc_module_begin() set_shortname("mtm") set_description(N_("libmtm MTM support")) set_capability("access", 20) set_category(CAT_INPUT) set_subcategory(SUBCAT_INPUT_ACCESS) set_callbacks(Open, Close) vlc_module_end() static int Open(vlc_object_t *p_this){ return VLC_EGENERIC; } static inline void Close(vlc_object_t *obj){ }

I then run the make file. It has the effective command of:

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cc -std=gnu99 -I/home/user/projects/vlc/vlc/include -g -O2 -Wall -Wextra -fPIC -D__PLUGIN__ -D_FILE_OFFSET_BITS=64 -D_REENTRANT -D_THREAD_SAFE -I/usr/local/include -I/usr/local/include/vlc/plugins -shared -o libaccess_mtm_plugin.dll src/vlc_mtm_module.o -Wl,-no-undefined,-z,defs -L/usr/lib -L/usr/local/lib -lvlccore

Then I put it in the plugins/access directory.

Then I run vlc --reset-plugins-cache

Is there some part of the process I've missed or is something wrong with my make command? Any help is greatly appreciated.

[Rémi Denis-Courmont]

Are you sure you built a Windows DLL, and not a Linux ELF shared object there?

[Lehm]

Oh I'm unsure of anything at this point. I did look at the file in hex and I see the letters ELF at the beginning so I probably have an ELF shared object. I've spent the last 4 hours trying to figure out how to change it to produce a Windows DLL. Including looking at tutorials, reading the man files, going over the VLC info pages again. Nothing I've done seems to work. Got an example I can look at so I can see what I've got wrong?

[Lehm]

Okay I think I've made a bit more progress. I've learned that you have to use the correct compiler. I was looking for an option in the one I was using. So I've updated my build command to:

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x86_64-w64-mingw32-gcc -I/home/jeffadams/projects/vlc/vlc/include -fPIC -D__PLUGIN__ -D_FILE_OFFSET_BITS=64 -D_REENTRANT -D_THREAD_SAFE -I/usr/local/include -I/usr/local/include/vlc/plugins -shared -o libaccess_mtm_plugin.dll -Wl,-out-implib=libaccess_mtm_plugin.dll.a,-no-undefined src/vlc_mtm_module.o -L/usr/lib -L./lib -L/usr/local/lib -lvlccore

It looks like I am now building a Windows DLL as far as I can tell. However it still does not show up in vlc when placed in the plugins directory.

[Rémi Denis-Courmont]

You need the compiler, linker and their respective flags to match.

Typically, example Makefiles cover native compilation for the sake of simplicity, and also partly by convention.

[Lehm]

Hmm... I've been trying the past two days to figure out what doesn't match. I can't find it. Is it the define flags? Are those wrong for a Windows Build?

[Jean-Baptiste Kempf]

Hmm... I've been trying the past two days to figure out what doesn't match. I can't find it. Is it the define flags? Are those wrong for a Windows Build?

When you launch VLC from a terminal with -vvv --list, it will show in yellow why some modules are not loaded.