Added basic usage print

1 files changed, 9 insertions, 1 deletions

diff --git a/markdown.cpp b/markdown.cpp
index ddad512..358edcf 100644
--- a/markdown.cpp
+++ b/markdown.cpp
@@ -54,10 +54,18 @@ static void resized(GLFWwindow *, int width, int height)
 	g_window_size.y = static_cast<float>(height);
 }
 
+static void print_usage(const char * program)
+{
+	std::cerr << "Usage: " << program << " FILE" << std::endl;
+}
+
 int main(int argc, char ** argv)
 {
 	if (2 != argc)
-		return 1;
+	{
+		print_usage(argv[0]);
+		return 2;
+	}
 
 	glfwSetErrorCallback(glfw_error_callback);
 	if (!glfwInit())