Implicit declaration of function 'FillOutASBDForLPCM' is invalid in C99 - ios

Question

When implementing the predefined inline C++ method, I am getting
Implicit declaration of function 'FillOutASBDForLPCM' is invalid in
C99
error. Please help me what i made the mistake or Do i import or add anything to access C++ method. I added this function, whenever I try to compile I am getting error.
void Convert()
{
//File URLs
CFURLRef micUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kMicFilePath, kCFURLPOSIXPathStyle, false);
CFURLRef speakerUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kSpeakerFilePath, kCFURLPOSIXPathStyle, false);
CFURLRef mixUrl = CFURLCreateWithFileSystemPath(NULL, (CFStringRef)kResultFilePath, kCFURLPOSIXPathStyle, false);
ExtAudioFileRef micFile = NULL;
ExtAudioFileRef speakerFile = NULL;
ExtAudioFileRef mixFile = NULL;
//Opening input files (speaker and mic)
ExtAudioFileOpenURL(micUrl, &micFile);
ExtAudioFileOpenURL(speakerUrl, &speakerFile);
//Reading input file audio format (mono LPCM)
AudioStreamBasicDescription inputFormat, outputFormat;
UInt32 descSize = sizeof(inputFormat);
ExtAudioFileGetProperty(micFile, kExtAudioFileProperty_FileDataFormat, &descSize, &inputFormat);
int sampleSize = inputFormat.mBytesPerFrame;
//Filling input stream format for output file (stereo LPCM)
FillOutASBDForLPCM(inputFormat, inputFormat.mSampleRate, 2, inputFormat.mBitsPerChannel, inputFormat.mBitsPerChannel, true, false, false);
//Filling output file audio format (AAC)
memset(&outputFormat, 0, sizeof(outputFormat));
outputFormat.mFormatID = kAudioFormatMPEG4AAC;
outputFormat.mSampleRate = 8000;
outputFormat.mFormatFlags = kMPEG4Object_AAC_Main;
outputFormat.mChannelsPerFrame = 2;
//Opening output file
ExtAudioFileCreateWithURL(mixUrl, kAudioFileM4AType, &outputFormat, NULL, kAudioFileFlags_EraseFile, &mixFile);
ExtAudioFileSetProperty(mixFile, kExtAudioFileProperty_ClientDataFormat, sizeof(inputFormat), &inputFormat);
//Freeing URLs
CFRelease(micUrl);
CFRelease(speakerUrl);
CFRelease(mixUrl);
//Setting up audio buffers
int bufferSizeInSamples = 64 * 1024;
AudioBufferList micBuffer;
micBuffer.mNumberBuffers = 1;
micBuffer.mBuffers[0].mNumberChannels = 1;
micBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples;
micBuffer.mBuffers[0].mData = malloc(micBuffer.mBuffers[0].mDataByteSize);
AudioBufferList speakerBuffer;
speakerBuffer.mNumberBuffers = 1;
speakerBuffer.mBuffers[0].mNumberChannels = 1;
speakerBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples;
speakerBuffer.mBuffers[0].mData = malloc(speakerBuffer.mBuffers[0].mDataByteSize);
AudioBufferList mixBuffer;
mixBuffer.mNumberBuffers = 1;
mixBuffer.mBuffers[0].mNumberChannels = 2;
mixBuffer.mBuffers[0].mDataByteSize = sampleSize * bufferSizeInSamples * 2;
mixBuffer.mBuffers[0].mData = malloc(mixBuffer.mBuffers[0].mDataByteSize);
//Converting
while (true)
{
//Reading data from input files
UInt32 framesToRead = bufferSizeInSamples;
ExtAudioFileRead(micFile, &framesToRead, &micBuffer);
ExtAudioFileRead(speakerFile, &framesToRead, &speakerBuffer);
if (framesToRead == 0)
{
break;
}
//Building interleaved stereo buffer - left channel is mic, right - speaker
for (int i = 0; i < framesToRead; i++)
{
memcpy((char*)mixBuffer.mBuffers[0].mData + i * sampleSize * 2, (char*)micBuffer.mBuffers[0].mData + i * sampleSize, sampleSize);
memcpy((char*)mixBuffer.mBuffers[0].mData + i * sampleSize * 2 + sampleSize, (char*)speakerBuffer.mBuffers[0].mData + i * sampleSize, sampleSize);
}
//Writing to output file - LPCM will be converted to AAC
ExtAudioFileWrite(mixFile, framesToRead, &mixBuffer);
}
//Closing files
ExtAudioFileDispose(micFile);
ExtAudioFileDispose(speakerFile);
ExtAudioFileDispose(mixFile);
//Freeing audio buffers
free(micBuffer.mBuffers[0].mData);
free(speakerBuffer.mBuffers[0].mData);
free(mixBuffer.mBuffers[0].mData);
}

Answer 1

Provided you have this function included from CoreAudio framework:
#import <CoreAudio/CoreAudio.h>
You merely need to inform the compiler that the code takes C++ code. Provided it's a mixed with Objective-C code file, you apparently want it to be of .mm format OR need to specify the language explicitly when compiling the file with use of -ObjC++ flag (in addition to other parameters):
% clang -ObjC++ MyFile.m