Xcode cannot find label 'error' for PortAudio - c++

Question

I'm attempting to initialise portaudio as described in the Initialising PortAudio tutorial.
It says to check if there was an error during initialisation like so:
PaError err = Pa_Initialize();
if (err != paNoError) goto error;
Which is the exact code I'm using.
I'm running this on OS X Mojave 10.14.4, using Xcode 10.1 with the 10.12 OS X SDK.
I've attempted to find where the error label in the PortAudio docs to no avail, and there are no variables in the file named error.
The full program so far is:
# include <iostream>
# include "portaudio.h"
using namespace std;
// Typedef and demo callbacks here.
int main(int argc, const char * argv[])
{
PaError err = Pa_Initialize();
if (err != paNoError) goto error;
// Nothing here yet.
err = Pa_Terminate();
if (err != paNoError)
{
printf("Port audio error terminating: %s", Pa_GetErrorText(err));
}
return 0;
}
As far as I can tell in the tutorial, this should be a valid statement, but Xcode shows the syntax error:
Use of undeclared label 'error'

Answer 1

Inspecting the c++ reference for goto statements an example program for PortAudio, the problem came from assuming that goto can access things defined in the portaudio.h file, which is not the case.
If you're having this issue, I assume you're also unfamiliar with goto statements.
The tutorial assumes there's a section of the main function dedicated to resolving errors. In order to resolve this issue, we need to define an error label in our main function that takes care of responding to errors.
For example:
int main(void) {
PaError err;
// Checking for errors like in the question code, including goto statement.
return 1; // If everything above this goes well, we return success.
error: // Tells the program where to go in the goto statement.
Pa_Terminate(); // Stop port audio. Important!
fprintf( stderr, "We got an error: %s/n", Pa_GetErrorMessage(err));
return err;
}