From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 23 Oct 2016 12:35:24 +0000 (+0300)
Subject: Check glGetString result for being null
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=cf89f0205dfad2c8df47217e34302da71bbeda01

Check glGetString result for being null
---

diff --git a/source/extension.cpp b/source/extension.cpp
index 8512046f..e233ee00 100644
--- a/source/extension.cpp
+++ b/source/extension.cpp
@@ -81,18 +81,21 @@ bool is_supported(const string &ext)
 			extensions.insert(exts.begin(), exts.end());
 		}
 
-		string renderer = reinterpret_cast<const char *>(glGetString(GL_RENDERER));
-		if(renderer.find("Radeon")!=string::npos || renderer.find("AMD")!=string::npos)
+		if(const char *renderer_ptr = reinterpret_cast<const char *>(glGetString(GL_RENDERER)))
 		{
-			/* Radeon doesn't process NV_primitive_restart correctly and treats
-			the restart index as a normal element if the indices are stored in a
-			buffer. */
-			extensions.erase("GL_NV_primitive_restart");
-
-			/* AMD's uniform buffer objects only work with the core version of
-			shaders. */
-			if(!(get_gl_version()>=Version(2, 0)))
-				extensions.erase("GL_ARB_uniform_buffer_object");
+			string renderer = renderer_ptr;
+			if(renderer.find("Radeon")!=string::npos || renderer.find("AMD")!=string::npos)
+			{
+				/* Radeon doesn't process NV_primitive_restart correctly and treats
+				the restart index as a normal element if the indices are stored in a
+				buffer. */
+				extensions.erase("GL_NV_primitive_restart");
+
+				/* AMD's uniform buffer objects only work with the core version of
+				shaders. */
+				if(!(get_gl_version()>=Version(2, 0)))
+					extensions.erase("GL_ARB_uniform_buffer_object");
+			}
 		}
 
 		if(const char *disable_ptr = getenv("MSPGL_DISABLE_EXTENSIONS"))
@@ -119,7 +122,11 @@ GLApi get_gl_api()
 
 inline Version _get_gl_version()
 {
-	string gl_ver = reinterpret_cast<const char *>(glGetString(GL_VERSION));
+	const char *gl_ver_ptr = reinterpret_cast<const char *>(glGetString(GL_VERSION));
+	if(!gl_ver_ptr)
+		throw runtime_error("OpenGL version not available");
+
+	string gl_ver = gl_ver_ptr;
 	if(!gl_ver.compare(0, 10, "OpenGL ES "))
 		gl_ver.erase(0, 10);
 
@@ -143,7 +150,11 @@ const Version &get_gl_version()
 
 inline Version _get_glsl_version()
 {
-	string glsl_ver = reinterpret_cast<const char *>(glGetString(GL_SHADING_LANGUAGE_VERSION));
+	const char *glsl_ver_ptr = reinterpret_cast<const char *>(glGetString(GL_SHADING_LANGUAGE_VERSION));
+	if(!glsl_ver_ptr)
+		throw runtime_error("GLSL version not available");
+
+	string glsl_ver = glsl_ver_ptr;
 	if(!glsl_ver.compare(0, 18, "OpenGL ES GLSL ES "))
 		glsl_ver.erase(0, 18);