15 Oct
2014
15 Oct
'14
8:24 p.m.
Hello LADs
I'm trying to make a GUI for a LV2 synth based on so-404. In fact, I'm
trying to learn C / C++.
I got everything to build OK, but I'm stuck on a hard to read execution
error ; when I load the plugin in jalv, it loads it OK, but fails to
load the UI and says :
suil error: Unable to open UI library
/usr/local/lib/lv2/kis.lv2/kis_gui.so
(/usr/local/lib/lv2/kis.lv2/kis_gui.so: undefined symbol:
_Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature)
(The architecture is based on
https://github.com/harryhaaren/lv2/tree/master/plugins/eg-sinsynth.lv2
in fact it is exactly the same : synth.c/h, synth_gui.cpp, widget.cpp/h,
built as synth.so synth_gui.so synth.ttl and manifest.ttl using waf).
I must say I'm still to fully understand the concept of descriptors...
Can somebody see what I'm doing wrong?
Thanks
--Philippe "xaccrocheur" Coatmeur
15 Oct
15 Oct
9:17 p.m.
On Wed, Oct 15, 2014 at 2:24 PM, Phil CM <philcm(a)gnu.org> wrote:
Hello LADs
I'm trying to make a GUI for a LV2 synth based on so-404. In fact, I'm
trying to learn C / C++.
I got everything to build OK, but I'm stuck on a hard to read execution
error ; when I load the plugin in jalv, it loads it OK, but fails to load
the UI and says :
suil error: Unable to open UI library /usr/local/lib/lv2/kis.lv2/kis_gui.so
(/usr/local/lib/lv2/kis.lv2/kis_gui.so: undefined symbol:
_Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature)
% echo _Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature |
c++filt
instantiateSO_404(_LV2_Descriptor const*, double, char const*, _LV2_Feature
const* const*)
%
your plugin is missing a symbol (instantiateSO_404(...)), apparently.
9:42 p.m.
On 15/10/14 20:17, Paul Davis wrote:
On Wed, Oct 15, 2014 at 2:24 PM, Phil CM <philcm(a)gnu.org
<mailto:philcm@gnu.org>> wrote:
Hello LADs
I'm trying to make a GUI for a LV2 synth based on so-404. In fact,
I'm trying to learn C / C++.
I got everything to build OK, but I'm stuck on a hard to read
execution error ; when I load the plugin in jalv, it loads it OK,
but fails to load the UI and says :
suil error: Unable to open UI library
/usr/local/lib/lv2/kis.lv2/kis_gui.so
(/usr/local/lib/lv2/kis.lv2/kis_gui.so: undefined symbol:
_Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature)
% echo _Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature
| c++filt
Wow, now that is a nice tool, thanks (a /lot/) for the tip!
instantiateSO_404(_LV2_Descriptor const*, double, char
const*,
_LV2_Feature const* const*)
%
your plugin is missing a symbol (instantiateSO_404(...)), apparently.
In my kis.h
file, required in my kis.c file, I have this
LV2_Handle instantiateSO_404(const LV2_Descriptor *descriptor,double
s_rate, const char *path,const LV2_Feature * const* features);
static LV2_Descriptor kis_Descriptor= {
.URI="https://bitbucket.org/xaccrocheur/kis",
.instantiate=instantiateSO_404,
.connect_port=connectPortSO_404,
.activate=NULL,
.run=runSO_404,
.deactivate=NULL,
.cleanup=cleanupSO_404,
.extension_data=NULL,
};
And in the kis.c file is a
LV2_Handle instantiateSO_404(const LV2_Descriptor* descriptor,double
s_rate, const char *path,const LV2_Feature * const* features) {
so_404* so=malloc(sizeof(so_404));
LV2_URI_Map_Feature *map_feature;
const LV2_Feature * const * ft;
for (ft = features; *ft; ft++) {
if (!strcmp((*ft)->URI, "http://lv2plug.in/ns/ext/uri-map")) {
map_feature = (*ft)->data;
so->midi_event_id = map_feature->uri_to_id(
map_feature->callback_data,
"http://lv2plug.in/ns/ext/event",
"http://lv2plug.in/ns/ext/midi#MidiEvent");
} else if (!strcmp((*ft)->URI, "http://lv2plug.in/ns/ext/event")) {
so->event_ref = (*ft)->data;
}
}
puts( "SO-404 v.1.2 by 50m30n3 2009-2011" );
so->phase = 0.0;
so->freq = 440.0;
so->tfreq = 440.0;
so->amp = 0.0;
so->env=0.0;
so->vel=0;
so->fcutoff = 0.0;
so->fspeed = 0.0;
so->fpos = 0.0;
so->lastsample = 0.0;
so->noteson = 0;
so->cdelay = s_rate/100;
so->samplerate=s_rate;
so->release = 100;
so->cutoff = 50;
so->envmod = 80;
so->resonance = 100;
so->volume = 100;
so->portamento = 64;
return so;
}
And in the gui file, indeed :
static LV2UI_Descriptor descriptors[] = {
{KIS_UI_URI, instantiate, cleanup, port_event, extension_data}
};
const LV2UI_Descriptor * lv2ui_descriptor(uint32_t index) {
printf("lv2ui_descriptor(%u) called\n", (unsigned int)index);
if (index >= sizeof(descriptors) / sizeof(descriptors[0])) {
return NULL;
}
return descriptors + index;
// return NULL;
}
How does that work?
* Is the UI always supposed to return the instantiate handle?
* How is it supposed to return it?
Thanks a lot,
--Phil
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10:26 p.m.
On 15/10/14 20:17, Paul Davis wrote:
On Wed, Oct 15, 2014 at 2:24 PM, Phil CM <philcm(a)gnu.org
<mailto:philcm@gnu.org>> wrote:
Hello LADs
I'm trying to make a GUI for a LV2 synth based on so-404. In fact,
I'm trying to learn C / C++.
I got everything to build OK, but I'm stuck on a hard to read
execution error ; when I load the plugin in jalv, it loads it OK,
but fails to load the UI and says :
suil error: Unable to open UI library
/usr/local/lib/lv2/kis.lv2/kis_gui.so
(/usr/local/lib/lv2/kis.lv2/kis_gui.so: undefined symbol:
_Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature)
% echo _Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature
| c++filt
instantiateSO_404(_LV2_Descriptor const*, double, char const*,
_LV2_Feature const* const*)
%
your plugin is missing a symbol (instantiateSO_404(...)), apparently.
The problem
seems to be different implementations of instantiate().
In Harry's example
<https://github.com/harryhaaren/lv2/tree/master/plugins/eg-sinsynth.lv2>, the
methods that (AFAIU) LV2 expects :
* instantiate()
* connect_port()
* activate()
* run()
* deactivate()
* cleanup()
* extension_data()
Are declared explicitely, using static.
Like this :
static LV2_Handle
instantiate(const LV2_Descriptor* descriptor,
double rate,
const char* bundle_path,
const LV2_Feature* const* features)
{
SinSynth* self = (SinSynth*)malloc(sizeof(SinSynth));
// store the sample rate in "self" so we can retrieve it in run()
self->sample_rate = rate;
// initialize the phase so we start at the beginning of the wave
self->phase = 0.f;
return self;
}
void
connect_port(LV2_Handle instance,
uint32_t port,
void* data)
{
SinSynth* self=(SinSynth*)instance;
switch (port) {
case AMP_FREQ:
self->freq = (float*)data;
break;
case AMP_MIDI:
self->MidiIn = data;
break;
case AMP_OUTPUT:
self->output = (float*)data;
break;
}
}
static void
activate(LV2_Handle instance)
{
}
(...)
Whereas in so-404, they are somehow "surcharged", like this :
void runSO_404( LV2_Handle arg, uint32_t nframes );
LV2_Handle instantiateSO_404(const LV2_Descriptor *descriptor,double
s_rate, const char *path,const LV2_Feature * const* features);
void cleanupSO_404(LV2_Handle instance);
void connectPortSO_404(LV2_Handle instance, uint32_t port, void
*data_location);
static LV2_Descriptor kis_Descriptor= {
.URI="https://bitbucket.org/xaccrocheur/kis",
.instantiate=instantiateSO_404,
.connect_port=connectPortSO_404,
.activate=NULL,
.run=runSO_404,
.deactivate=NULL,
.cleanup=cleanupSO_404,
.extension_data=NULL,
};
So apparently instead of being declared thusly:
LV2_Handle
instantiateSO_404(const LV2_Descriptor* descriptor,
double s_rate,
const char *path,
const LV2_Feature * const* features)
{...}
Either my instantiate method return value should be static, or my
"mandatory" methods should be declared explicitely. I tried to adapt
them, but failed so far.
Please excuse my sub-newbie mistakes.
--Phil
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16 Oct
16 Oct
12:16 p.m.
On 10/15/2014 08:24 PM, Phil CM wrote:
suil error: Unable to open UI library
/usr/local/lib/lv2/kis.lv2/kis_gui.so
(/usr/local/lib/lv2/kis.lv2/kis_gui.so: undefined symbol:
_Z17instantiateSO_404PK15_LV2_DescriptordPKcPKPK12_LV2_Feature)
remove "static" for declaration of instantiateSO_404, both
in kis.h and kis.c.
static is not a type, it's a "scope" thing.
When you do:
static void function(void) {}
in a file, it basically means that this function does
not exist out of the file where you define it.
With this mechanism you can create many many "void function(void) {}"
in various source files and putting all together in a single
program will just work TM. Without "static" you would have a clash
at link time, because of more than one declaration for a symbol.
(Speaking C here, C++ might be different, I don't know.)
And yes, this is very often used.
But in your case, you must not use it.
Then, in mix.h you should add the 3 lines:
#ifdef __cplusplus
extern "C" {
#endif
near the top (let's say after all the #include lines)
and at the very end, the 3 lines:
#ifdef __cplusplus
}
#endif
Why?
Because kis.c is a C file and thus defines a C function.
C++ is different with functions. It will "mangle" function
names, so that "void toto(int x)" becomes "_Z4totoi" (with gcc,
might be different with various compilers; as far as I know there
is no standard for mangling names, but I might be wrong here,
c++ is not my cup of orange juice).
You run "c++filt _Z4totoi" to see the unmangled name.
Why is it needed? Because in C++ we have "signatures", not
"function names", so you may well have "void toto(int x)" and
"void toto(float x)". That can't exist in C.
And to tell the C++ compiler that the function XXX is a C function
and not a C++ you need the 'extern "C"' thing.
The #ifdef __cplusplus is there to be able to use the .h file
with both a C and a C++ compiler because 'extern "C"' is a C++
thing and a C compiler won't eat it.
Anyway, just add the six lines above.
Then, well, I tried to run with that and I still have a failure
on the symbol instantiateSO_404 (you see that this time it is
not mangled anymore).
To see something popup I had to run in the 'build' directory:
gcc -shared -pthread widget.cpp.4.o kis_gui.cpp.4.o -o
kis.lv2/kis_gui.so -Wl,-Bdynamic -L/tmp/aa/lib -lntk -lcairo ../kis.c
-I../../include -fPIC
(path adjustement needed if you want to reproduce)
followed by "waf install" in the upper directory.
I basically include "kis.c" in "kui_gui.so".
Then running:
jalv.gtk https://bitbucket.org/xaccrocheur/kis
sees a window popup with a menu and a slider.
I didn't test audio output. Jack is an alien beast
on my computer and today I was not into giving it
more life than a -d dummy run.
Maybe those more familiar with the lv2 bloat will be
able to help you, I can't go further than that, sorry,
my feet refuse to walk some dark territories of unnecessary
complexity.
HTH
C.
12:53 p.m.
On 16/10/14 11:14, Cedric Roux wrote:
remove "static" for declaration of instantiateSO_404, both
in kis.h and kis.c.
(...)
Then, in mix.h you should add the 3 lines:
#ifdef __cplusplus
extern "C" {
#endif
near the top (let's say after all the #include lines)
and at the very end, the 3 lines:
#ifdef __cplusplus
}
#endif
(...)
To see something popup I had to run in the
'build' directory:
gcc -shared -pthread widget.cpp.4.o kis_gui.cpp.4.o -o
kis.lv2/kis_gui.so -Wl,-Bdynamic -L/tmp/aa/lib -lntk -lcairo ../kis.c
-I../../include -fPIC
(path adjustement needed if you want to reproduce)
followed by "waf install" in the upper directory.
I basically include "kis.c" in "kui_gui.so".
Then running:
jalv.gtk https://bitbucket.org/xaccrocheur/kis
sees a window popup with a menu and a slider.
(...)
Oh Mon Dieu, it works. Cedric, thank you very much for your light. All
those infos are exactly what I needed ;
Those atrocious begginer errors were hard to spot, let alone correct,
and I find it hard to thank you enough to have taken the time to put me
back on track.
Now I need to learn waf to get it to build this :)
Phil
3:10 p.m.
On 10/16/2014 12:53 PM, Phil CM wrote:
Oh Mon Dieu, it works. Cedric, thank you very much for
your light. All
those infos are exactly what I needed ;
Those atrocious begginer errors were hard to spot, let alone correct,
and I find it hard to thank you enough to have taken the time to put me
back on track.
Now I need to learn waf to get it to build this :)
good luck...
waf...
let's not troll...
But wait!
I now know why it failed.
This:
static LV2_Descriptor kis_Descriptor= {
.URI="https://bitbucket.org/xaccrocheur/kis",
.instantiate=instantiateSO_404,
.connect_port=connectPortSO_404,
.activate=NULL,
.run=runSO_404,
.deactivate=NULL,
.cleanup=cleanupSO_404,
.extension_data=NULL,
};
should be in kis.c, not kis.h
(put it right after #include "kis.h")
and then cleaning stuff (rm -rf build/*) and compiling again
pops up a window with jalv.gtk.
Putting the kis_Descriptor in kis.h file means that
every file that includes kis.h will declare kis_Descriptor.
In your case you really had 2 kis_Descriptor structures,
one in kis.so and one in kis_gui.so. Since you build
a .so file (shared library), gcc accepts to create it
even if instantiateSO_404 does not exist at compilation
time. At runtime though, every symbol must be defined,
which is not the case here, leading to, well, failure.
Generally (in your beginner case: always) you *declare*
types and functions (declaration, not definition) in .h
files and *define* functions and global variables in .c (or .cpp
for c++) files. The .h is there to share definitions between
various c/c++ source files. (For a function, a "declaration"
is just "int toto(int x);" with no associated code. A "definition"
is "int toto(int x) { return x; }" you see, with actual code.
(You can do that with global variables too, but global
variables are a bad idea. Forget about those for the moment.)
Ah, and because you create a .so file, some special attention
is required with your definitions. With the "static" keyword
put in front of functions and global variables, you "hide"
those from the rest of the world. You want to do that for
all the functions and variables, except in your case
the functions "lv2_descriptor" and "lv2ui_descriptor"
which will be called by the host of your plugin.
Now if your project has more than one source file, you can't
use static (say file a.c calls a function in b.c). Then I
don't know. Maybe there is some linker magic to be specific
at what symbols must be exported. If someone knows...
(my friend laziness is calling me so hard! crazy little
beast deep inside my brain... wait! I'm coming!)
HTH
C.
5:28 p.m.
On 16/10/14 14:08, Cedric Roux wrote:
On 10/16/2014 12:53 PM, Phil CM wrote:
(...) (indispensable scoping & including info)
Dude, you really made my day. Now it builds without my clumsy script ;
thank you VERY much.
Please, have a (homemade <http://www.rncbc.org/drupal/node/307>) song
<http://opensimo.com/play/?a=Azer0,Counternatures&play=1>.
Phil
Oh Mon Dieu, it works. Cedric, thank you very
much for your light. All
those infos are exactly what I needed ;
Those atrocious begginer errors were hard to spot, let alone correct,
and I find it hard to thank you enough to have taken the time to put me
back on track.
Now I need to learn waf to get it to build this :)
good luck...
waf...
let's not troll...
But wait!
I now know why it failed.
This:
static LV2_Descriptor kis_Descriptor= {
.URI="https://bitbucket.org/xaccrocheur/kis",
.instantiate=instantiateSO_404,
.connect_port=connectPortSO_404,
.activate=NULL,
.run=runSO_404,
.deactivate=NULL,
.cleanup=cleanupSO_404,
.extension_data=NULL,
};
should be in kis.c, not kis.h
(put it right after #include "kis.h")
and then cleaning stuff (rm -rf build/*) and compiling again
pops up a window with jalv.gtk. HTH
C.
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9 comments
3 participants
participants (3)
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Cedric Roux -
Paul Davis -
Phil CM