Function perr

dependencies/libusb-1.0.22/examples/source/xusb.c:61–68

static const char* binary_name = NULL;

static void perr(char const *format, ...)
{
	va_list args;

	va_start (args, format);
	vfprintf(stderr, format, args);
	va_end(args);
}

#define ERR_EXIT(errcode) do { perr("   %s\n", libusb_strerror((enum libusb_error)errcode)); return -1; } while (0)
#define CALL_CHECK(fcall) do { int _r=fcall; if (_r < 0) ERR_EXIT(_r); } while (0)