veracrypt.m

  NSString * passwordString = @"b";
  NSString * mountPoint = @"/a";
    
  NSTask * veraCrypt = [[NSTask alloc] init];
  [veraCrypt setLaunchPath:@"/Applications/VeraCrypt.app/Contents/MacOS/VeraCrypt"];
  [veraCrypt setArguments:@[@"-t", @"--mount", mountPoint]];
    
  NSPipe * inputPipe = [NSPipe pipe];
  [veraCrypt setStandardInput:inputPipe];
    
  NSString * inputString = [NSString stringWithFormat:@"\n%@\n\n\n", passwordString];
  NSData * inputData = [inputString dataUsingEncoding:[NSString defaultCStringEncoding]];
  [[inputPipe fileHandleForWriting] writeData:inputData];
    
  [veraCrypt launch];
  [veraCrypt waitUntilExit];