From 44252b3f41e43b579dfdc58bb962b1faf49ee1e7 Mon Sep 17 00:00:00 2001
From: Yurii Nakonechnyi <inobelar@gmail.com>
Date: Fri, 25 Sep 2020 00:39:20 +0300
Subject: [PATCH]  Added GLFW error-callback into FlutterEmbedderGLFW
 (flutter/engine#19998)

GLFW Error callback useful to clarify reasons of 'glfwInit()' failure.

On some platforms/desktop environments may be really strange failure reasons, like (in my case): "Linux: Failed to initialize inotify: Too many open files", so descriptive error messages helps to solve problem.
---
 engine/src/flutter/examples/glfw/FlutterEmbedderGLFW.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/engine/src/flutter/examples/glfw/FlutterEmbedderGLFW.cc b/engine/src/flutter/examples/glfw/FlutterEmbedderGLFW.cc
index 4dfffad4e60..419630a733c 100644
--- a/engine/src/flutter/examples/glfw/FlutterEmbedderGLFW.cc
+++ b/engine/src/flutter/examples/glfw/FlutterEmbedderGLFW.cc
@@ -129,6 +129,10 @@ void printUsage() {
             << std::endl;
 }
 
+void GLFW_ErrorCallback(int error, const char* description) {
+  std::cout << "GLFW Error: (" << error << ") " << description << std::endl;
+}
+
 int main(int argc, const char* argv[]) {
   if (argc != 3) {
     printUsage();
@@ -138,6 +142,8 @@ int main(int argc, const char* argv[]) {
   std::string project_path = argv[1];
   std::string icudtl_path = argv[2];
 
+  glfwSetErrorCallback(GLFW_ErrorCallback);
+
   int result = glfwInit();
   assert(result == GLFW_TRUE);