va_list args;

va_start(args, fmt);

#ifdef __ANDROID__

__android_log_vprint(ANDROID_LOG_INFO, componentName, fmt, args);

#elif defined(__APPLE__)

static os_log_t hermesLogger = os_log_create("dev.hermesengine", "Default");

// Need to make a copy in order to do the vsprintf trick.

va_list argsCopy;

va_copy(argsCopy, args);

int numChars = vsnprintf(nullptr, 0, fmt, argsCopy);

va_end(argsCopy);

std::unique_ptr<char[]> buffer{new char[numChars + 1]};

int numCharsWritten = vsnprintf(buffer.get(), numChars + 1, fmt, args);

(void)numCharsWritten;

// Log all messages as public here. Hermes will never log private information.

os_log_with_type(

hermesLogger,

OS_LOG_TYPE_INFO,

"%{public}s: %{public}s",

componentName,

buffer.get());

#else

fprintf(stderr, "%s: ", componentName);

vfprintf(stderr, fmt, args);

fprintf(stderr, "\n");

#endif

va_end(args);