c++ - glfw3 compiling undefined references

Question

I have a problem with compiling my program which uses glfw3 library.

I'm getting list of errors of undefined references when trying to compile with make but my classes are compiled into .o files, only final executable file is not created.

stdout:

g++ -Wall -g -c main.cpp -lGL -lGLU -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi 

g++ -Wall -g -c error.cpp -lGL -lGLU -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi

g++ -Wall -g -c sWindow.cpp -lGL -lGLU -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi 

g++ -Wall -g -o ecl main.o error.o sWindow.o -lGL -lGLU -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi

stderr:

/usr/local/lib/libglfw3.a(context.c.o): In function `parseGLVersion':
context.c:(.text+0x53): undefined reference to `glGetString'
/usr/local/lib/libglfw3.a(context.c.o): In function `_glfwRefreshContextAttribs':
context.c:(.text+0x907): undefined reference to `glGetIntegerv'
context.c:(.text+0x98a): undefined reference to `glGetIntegerv'
context.c:(.text+0x9df): undefined reference to `glGetIntegerv'
context.c:(.text+0xa32): undefined reference to `glGetIntegerv'
/usr/local/lib/libglfw3.a(context.c.o): In function `glfwExtensionSupported':
context.c:(.text+0xd59): undefined reference to `glGetString'
context.c:(.text+0xd93): undefined reference to `glGetIntegerv'
/usr/local/lib/libglfw3.a(window.c.o): In function `glfwCreateWindow':
window.c:(.text+0x6f8): undefined reference to `glClear'
/usr/local/lib/libglfw3.a(x11_time.c.o): In function `getRawTime':
x11_time.c:(.text+0x20): undefined reference to `clock_gettime'
/usr/local/lib/libglfw3.a(x11_time.c.o): In function `_glfwInitTimer':
x11_time.c:(.text+0x72): undefined reference to `clock_gettime'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `getFBConfigAttrib':
glx_context.c:(.text+0x51): undefined reference to `glXGetFBConfigAttrib'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `chooseFBConfig':
glx_context.c:(.text+0x7e): undefined reference to `glXGetClientString'
glx_context.c:(.text+0x104): undefined reference to `glXGetFBConfigs'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `createLegacyContext':
glx_context.c:(.text+0x43f): undefined reference to `glXCreateNewContext'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwInitContextAPI':
glx_context.c:(.text+0x48f): undefined reference to `glXQueryExtension'
glx_context.c:(.text+0x4ca): undefined reference to `glXQueryVersion'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwCreateContext':
glx_context.c:(.text+0x791): undefined reference to `glXGetVisualFromFBConfig'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwDestroyContext':
glx_context.c:(.text+0xd09): undefined reference to `glXDestroyContext'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwPlatformMakeContextCurrent':
glx_context.c:(.text+0xd55): undefined reference to `glXMakeCurrent'
glx_context.c:(.text+0xd70): undefined reference to `glXMakeCurrent'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwPlatformSwapBuffers':
glx_context.c:(.text+0xdc2): undefined reference to `glXSwapBuffers'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwPlatformExtensionSupported':
glx_context.c:(.text+0xe69): undefined reference to `glXQueryExtensionsString'
/usr/local/lib/libglfw3.a(glx_context.c.o): In function `_glfwPlatformGetProcAddress':
glx_context.c:(.text+0xeb1): undefined reference to `glXGetProcAddressARB'
collect2: ld returned 1 exit status
make: *** [ecl] Error 1

this is my makefile:

CXX = g++
CXXFLAGS = -Wall -g
LIBS = -lGL -lGLU -lglfw3 -lX11 -lXxf86vm -lXrandr -lpthread -lXi
DEPENDENCIES = main.o error.o sWindow.o

# ****************************************************
# Targets needed to bring the executable up to date

ecl: $(DEPENDENCIES)
    $(CXX) $(CXXFLAGS) -o ecl $(DEPENDENCIES) $(LIBS)

main.o: main.cpp
    $(CXX) $(CXXFLAGS) -c main.cpp $(LIBS)

error.o: error.cpp
    $(CXX) $(CXXFLAGS) -c error.cpp $(LIBS)

sWindow.o: sWindow.cpp
    $(CXX) $(CXXFLAGS) -c sWindow.cpp $(LIBS) 

clean: 
    rm -f *.o main
    echo "Clean done"

Do you have any idea what causes this and how to fix it?

Answer 1

Do it in this order:

-lglfw3 -lGLU -lGL

Instead of this one:

-lGL -lGLU -lglfw3

GCC is very sensitive to the order in which you specify libraries during the linking stage. For example, if libA.a depends on libB.a, then you'd have to invoke linker in the following way:

gcc ... -lA -lB ...

In your case, libglfw3.a obviously depends on libGL.a, hence the errors you are getting.