Adding C module to rom in eLua 0.10

[grahams]

Hi All,

I'm trying to add a C module to my 0.10 eLua rom image.  I've used the instructions at http://wiki.eluaproject.net/Tutorials/cmodules as a guide but I do not understand how to add my module to the rom.  I can see that my module has been compiled and has an entry in the .map file.  When I try and access it on my development board though I get an "attempt to index global 'json' (a nil value)" error.  Can anyone point out what I've failed todo?

Thanks,

Graham.

[jbsnyder]

Hi,

That tutorial needs to be updated since it is written for the older SCons-based build system.  The newer Lua-based build system handles things a bit differently.

At this point I believe you may only need to extend the elua_generic_modules table in conf/modules.lua (https://github.com/elua/elua/blob/master/config/modules.lua#L25), by adding, a line like:

json = {},

Let me know if that works.

Best.

-jsnyder

On Tue, Mar 24, 2015 at 11:30 AM, grahams [via eLua Development] <[hidden email]> wrote:

Hi All,

I'm trying to add a C module to my 0.10 eLua rom image.  I've used the instructions at http://wiki.eluaproject.net/Tutorials/cmodules as a guide but I do not understand how to add my module to the rom.  I can see that my module has been compiled and has an entry in the .map file.  When I try and access it on my development board though I get an "attempt to index global 'json' (a nil value)" error.  Can anyone point out what I've failed todo?

Thanks,

Graham.

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[grahams]

I think I may be nearly there,

Adding "json = {}" made a difference but has not fixed it.  When I start lua from the terminal I now get "lua: attempt to index a function value" output and the lua interrupter fails to start.

Graham

[jbsnyder]

Hi Graham,

Could you provide the luaopen & map definitions from your file?  I suspect the issue might be there.  Also, are you running a script or just starting up the Lua prompt with no arguments?

If you can't provide that, see the other modules in src/modules for how these portions should be set up.

I was able to take the tutorial on the wiki and with a few minor edits plus what I recommended I had it working in the image.  I've saved a few quick changes to that to be more consistent with the current build system.

Best.

-jsnyder

On Tue, Mar 24, 2015 at 12:29 PM, grahams [via eLua Development] <[hidden email]> wrote:

I think I may be nearly there,

Adding "json = {}" made a difference but has not fixed it.  When I start lua from the terminal I now get "lua: attempt to index a function value" output and the lua interrupter fails to start.

Graham

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[grahams]

It looks like I was registering the function incorrectly in the luaopen_json() function.  I was not using the LREGISTER macro.  Thank you for updating the wiki and your help.

Graham.