GLFW with GCC Mingw flags for static doesn't work as documented

Question

I want to learn openGL without relying on IDE configuring for me. But Seems that I have problems with correct flags. Before setting up Makefile for me it's easier to test with BAT file. my build.bat

set src=main.c
set output=main.exe
set include=%cd%\include
set lib=%cd%\lib

set compailer=gcc
set compFlags=-Wall
set linkFlags=-lglfw3 -lopengl32 -lgdi32 -luser32 -lkernel32

%compailer% %src% -o %output% %compFlags% -I %include% -L %lib% %linkFlags%

main.c has the same GLFW example code. In the project folder headers are in /include/GLFW and static lib in /lib with libglfw3.a .

when compiling I have long list of errors

D:\Dev\C\OpenGL>gcc main.c -o main.exe -Wall -I D:\Dev\C\OpenGL\include -L D:\Dev\C\OpenGL\lib -lglfw3 -lopengl32 -lgdi32 -luser32 -lkernel32
C:\Users\User\AppData\Local\Temp\cc2z12t2.o:main.c:(.text+0x7f): undefined reference to `_imp__glClear@4'
D:\Dev\C\OpenGL\lib/libglfw3.a(init.c.obj):init.c:(.text+0xb9): undefined reference to `__mingw_free'
D:\Dev\C\OpenGL\lib/libglfw3.a(init.c.obj):init.c:(.text+0xda): undefined reference to `__mingw_free'
...
D:\Dev\C\OpenGL\lib/libglfw3.a(win32_window.c.obj):win32_window.c:(.text+0x2383): undefined reference to `__mingw_free'
D:\Dev\C\OpenGL\lib/libglfw3.a(win32_window.c.obj):win32_window.c:(.text+0x4c0c): more undefined references to `__mingw_free' follow
collect2.exe: error: ld returned 1 exit status

I tried to follow the GLFW build guide .

Answer 1

Add -lmingw32 to your link flags. That should deal with __mingw_free at least I think.

Also -glut32 -glu32 perhaps.

According to the link you posted -lgdi32 -luser32 -lkernel32 are default libraries and need not be specified - should be harmless though.

Answer 2

I was having a very similar problem trying to do the exact same thing (My only difference was no undefined reference to _imp__glClear@4 , that only appeared when not using -lopengl32 ). I have fixed all the undefined reference to __mingw_free and __mingw_realloc by switching the glfw3 flag from -lglfw3 to -lglfw3dll . I am still learning so I don't know the real reason why this has fixed the problem.