Re: [Gumstix-users] Using and building the user-gpio source

[Dave H. <dhy...@gm...>]

Hi cciarleg,

On Sat, Jun 16, 2012 at 2:34 PM, cciarleg <cci...@um...> wrote:
> hmmmm, okay.  Unfortunately:
>
> oeuser@Falcon:~/overo-oe/user.collection/recipes/eyeballfly/files/lib$ ls
> libgpio.a  libgpio.so  Makefile  shared  static  user-gpio.c  user-gpio.h
>
> seems to have both static and shared libraries.
>
> and they definitely contain the functions that I want:
> oeuser@Falcon:~/overo-oe/user.collection/recipes/eyeballfly/files/lib$ nm
> libgpio.a
> user-gpio.o:
> 00000000 t $a
> 00000030 t $a
> 00000048 t $a
> 00000098 t $a
> 000000dc t $a
> 00000118 t $a
> 00000174 t $a
> 0000019c t $a
> 00000028 t $d
> 00000044 t $d
> 00000090 t $d
> 000000d4 t $d
> 00000114 t $d
> 0000016c t $d
> 00000198 t $d
> 000001d8 t $d
> 00000000 d $d
>         U __errno_location
>         U close
> 00000000 d gFd
> 000000dc T gpio_direction_input
> 00000098 T gpio_direction_output
> 00000030 T gpio_free
> 00000048 T gpio_get_value
> *0000019c T gpio_init*
> 00000118 T gpio_request
> 00000000 T gpio_set_value
> 00000174 T gpio_term
>         U ioctl
>         U open
>         U strncpy
>
> and (shortened):
> oeuser@Falcon:~/overo-oe/user.collection/recipes/eyeballfly/files/lib$ nm
> libgpio.so
> ....
> 0000897c a _DYNAMIC
> 00008a64 a _GLOBAL_OFFSET_TABLE_
>         w _Jv_RegisterClasses
> 0000096c r __FRAME_END__
> 00008978 d __JCR_END__
> 00008978 d __JCR_LIST__
> 00008aa4 A __bss_end__
> 00008aa0 A __bss_start
> 00008aa0 A __bss_start__
>         w __cxa_finalize@@GLIBC_2.4
> 00008a98 D __data_start
> 00000654 t __do_global_dtors_aux
> 00008974 t __do_global_dtors_aux_fini_array_entry
> 00008a98 d __dso_handle
> 00008aa4 A __end__
>         U __errno_location@@GLIBC_2.4
> 0000096c A __exidx_end
> 0000096c A __exidx_start
> 00008970 t __frame_dummy_init_array_entry
>         w __gmon_start__
> 00008aa4 A _bss_end__
> 00008aa0 A _edata
> 00008aa4 A _end
> 0000094c T _fini
> 000005b4 T _init
> 00000630 t call_gmon_start
>         U close@@GLIBC_2.4
> 00008aa0 b completed.6278
> 000006ac t frame_dummy
> 00008a9c d gFd
> 00000804 T gpio_direction_input
> 000007b4 T gpio_direction_output
> 00000734 T gpio_free
> 00000758 T gpio_get_value
> *000008f0 T gpio_init*
> 0000084c T gpio_request
> 000006f8 T gpio_set_value
> 000008b4 T gpio_term
>         U ioctl@@GLIBC_2.4
>         U open@@GLIBC_2.4
>         U strncpy@@GLIBC_2.4
>
> I think the bitbake files are fairly identical.  The only thing I don't
> understand in the gpio-app.bb is the module=app line.

The module=app is part of the SRC_URI and is telling it how to fetch
the source files from the repository (I think).

The module= portion gets appended to the part before it. I think I
just copied and pasted another module when I was doing that.

> What confuses me is
> that I don't get any complaints about the included library header file, and
> yet the function in the header file is not recognized.

It's important to distinguish compiler errors from linker errors. It
would be good to see the exact error messages that you're getting.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com