ios - How to load Sound Font -

i'm having no luck loading sound font file (.sf2) in ios app. tried using apple's code tech note tn2283

- (osstatus) loadfromdlsorsoundfont: (nsurl *)bankurl withpatch: (int)presetnumber {  osstatus result = noerr;  // fill out instrument data structure ausamplerinstrumentdata instdata; instdata.bankurl  = (cfurlref) bankurl; instdata.instrumenttype = kinstrumenttype_dlspreset; instdata.bankmsb  = kausampler_defaultmelodicbankmsb; instdata.banklsb  = kausampler_defaultbanklsb; instdata.presetid = (uint8) presetnumber;  // set kausamplerproperty_loadpresetfrombank property result = audiounitsetproperty(self.mysamplerunit,                               kausamplerproperty_loadinstrument,                               kaudiounitscope_global,                               0,                               &instdata,                               sizeof(instdata));  // check errors nscassert (result == noerr,            @"unable set preset property on sampler. error code:%d '%.4s'",            (int) result,            (const char *)&result);  return result; } 

but compiler complains 'no member named 'bankurl' in struct ausamplerinstrumentdata' true, struct not contain 'bankurl' member??

i came across following code, apple believe

- (osstatus)loadsoundfont:(nsurl *)bankurl withpatch:(int)presetnumber {     osstatus result = noerr;      // fill out bank preset data structure     ausamplerbankpresetdata bpdata;     bpdata.bankurl  = (__bridge cfurlref) bankurl;     bpdata.bankmsb  = kausampler_defaultmelodicbankmsb;     bpdata.banklsb  = kausampler_defaultbanklsb;     bpdata.presetid = (uint8) presetnumber;      // set kausamplerproperty_loadpresetfrombank property     result = audiounitsetproperty(self.samplerunit,                                   kausamplerproperty_loadpresetfrombank,                                   kaudiounitscope_global,                                   0,                                   &bpdata,                                   sizeof(bpdata));      // check errors     nscassert (result == noerr,                @"unable set preset property on sampler. error code:%d '%.4s'",                (int) result,                (const char *)&result);      return result; } 

this looks correct when attempt load sound font using method such follows

nsurl *sfurl = [[nsbundle mainbundle] urlforresource:@"yamaha dx7piano" withextension:@"sf2"]; [self loadsoundfont:url withpatch:0]; 

it throws error "unable set preset property on sampler.." did lead me think there error in how specified patch number, such supplying non-existent patch number. did discover nsurl supplying null, tried specifying url follows:

nsstring *resources = [[nsbundle mainbundle] resourcepath]; nsurl *sfurl = [nsurl fileurlwithpath:[nsstring stringwithformat:@"%@/%@",resources,@"yamaha dx7piano.sf2"]]; 

this has got me step closer. think supplying valid url sound font file in app bundle. still not working. compiler tells me

error: [0x19a824310] 486: dls/sf2 bank load failed

there piece of puzzle missing , can't see what.??

well found solution. sound font wasn't loading. wasn't loadoing because not added app bundle correctly. had dragged resources had add 'copy bundle resources' in project 'build phases'.