glewInit() "Missing GL Version" in CMake Release builds only - opengl

Question

I am building my OpenGL project using CMake with MSVC. It uses GLEW with GLFW. It runs fine when I build with --config Debug, but glewInit() fails when I run the build command with --config Release. I've tried both 64 and 32 bit builds, and it runs in debug but not release in both cases.
I've used add_definitions(-DGLEW_STATIC) in my CMakeLists.txt file to avoid needing #define GLEW_STATIC everywhere, but I've tried both and it doesn't make a difference.
I can see that the release glew.lib is getting produced (and glewd.lib gets produced for debug builds), and if I inspect the project properties in VS, the correct one is in the list of linker inputs.
I've tried with and without the window hints before creating a GL context.
There's something I don't understand going on here. Why is my GL version missing, only for Release build configuration?
EDIT: Adding minimum reproducible example (thanks squareskittles for the suggestion).
This is my CMakeLists.exe file:
cmake_minimum_required(VERSION 3.14)
project(Demo LANGUAGES CXX)
# Make sure GLEW gets built as a static lib
add_definitions(-DGLEW_STATIC)
option( glew-cmake_BUILD_SHARED "Build the shared glew library" OFF )
option( glew-cmake_BUILD_STATIC "Build the static glew library" ON )
# Build dependencies
add_subdirectory(glew)
add_subdirectory(glfw)
add_executable(demo demo/main.cpp)
target_compile_features(demo PUBLIC cxx_std_17)
target_compile_definitions(demo PRIVATE -D_SCL_SECURE_NO_WARNINGS)
target_include_directories(demo PUBLIC glew/include)
target_include_directories(demo PUBLIC glfw/include)
# Link dependencies
target_link_libraries(demo libglew_static glfw ${GLFW_LIBRARIES})
It might be important to know that glew-cmake is what is in my glew directory.
And demo/main.cpp:
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <cassert>
int main(int argc, char** argv)
{
// Open a window and initialize Glew
assert(glfwInit());
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
GLFWwindow* window = glfwCreateWindow(600, 400, "window", 0, 0);
glfwMakeContextCurrent(window);
std::cout << "GLFW: " << glfwGetVersionString() << "\n";
std::cout << "GLEW: " << glewGetString(GLEW_VERSION) << "\n";
GLenum glewStatus = glewInit();
if (glewStatus != GLEW_OK) {
std::cout << "GLEW ERROR: " << glewGetErrorString(glewStatus) << "\n";
exit(1);
}
std::cout << "GL: " << glGetString(GL_VERSION) << "\n";
// Shut down graphics
glfwDestroyWindow(window);
glfwTerminate();
return 0;
}
My build commands are run from a directory just below the level of my CMakeLists.txt file. My debug build command is:
cmake ..
cmake --build . --config Debug
If I build & run the debug executable, a window opens before terminating, and the output is:
GLFW: 3.3.0 Win32 WGL EGL VisualC
GLEW: 2.2.0
GL: 3.2.0 - Build 25.20.100.6617
And my release build command is:
cmake ..
cmake --build . --config Release
If I build & run the release executable, I hit the exit(1) line, and the output is:
GLFW: 3.3.0 Win32 WGL EGL VisualC
GLEW: 2.2.0
GLEW ERROR: Missing GL version
UPDATE: I've tried linking with shared libs (dlls) instead of static libs, and was confirmed that the bug still reproduces.
UPDATE: I tried building a VS project from scratch with only my minimum reproducible case, manually specifying either the static or dynamic linkages, and it actually works! So it seems like it must be something with my CMake configuration.

Answer 1

I found that I could get release builds to run with the exact same linkages if I manually set up a project in VS. I diffed the vcxproj file that I manually created with the one generated by CMake to figure out the differences in release configurations. It came down to the NDEBUG preprocessor definition.
I don't understand why this definition causes OpenGL not to be found (I suppose that's another question, but if you can answer it here I'll award you the answer). If I add the line
string( REPLACE "/DNDEBUG" "" CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
to my CMakeLists.txt file, I'm able to build and run in release mode!