使用makefile编译时出现链接器错误

Question

我正在使用ubuntu 14.04 LTS，并且正在研究着色示例程序。我有以下生成文件：

CC=gcc 
CFLAGS=-Wall -I/usr/X11R6/include 
LDFLAGS=-pthread -L/usr/X11R6/lib -lm -lGL -lglut 
OBJS=main.o scene.o shader.o 

glsl_lighting: $(OBJS) 
    $(CC) $(LDFLAGS) $(OBJS) -o glsl_lighting 

clean: 
    rm -f glsl_lighting 
    rm -f $(OBJS) 

main.o: main.c 
scene.o: scene.c 
shader.o: shader.c 

随着主文件之中的前几行：

#include <stdio.h> 
#include <stdlib.h> 
#include <math.h> 
#include "opengl.h" 

这给了以下错误：

gcc -pthread -L/usr/X11R6/lib -lm -lGL -lglut main.o scene.o shader.o -o glsl_lighting 
main.o: In function `handleKeyPress': 
main.c:(.text+0x27): undefined reference to `glutDestroyWindow' 
main.o: In function `setPerspective': 
main.c:(.text+0x65): undefined reference to `tanf' 
main.c:(.text+0x144): undefined reference to `glMultMatrixf' 
main.o: In function `main': 
main.c:(.text+0x168): undefined reference to `glutInit' 
main.c:(.text+0x172): undefined reference to `glutInitDisplayMode' 
main.c:(.text+0x185): undefined reference to `glutInitWindowSize' 
main.c:(.text+0x18f): undefined reference to `glutCreateWindow' 
main.c:(.text+0x19f): undefined reference to `glutDisplayFunc' 
main.c:(.text+0x1a9): undefined reference to `glutIdleFunc' 
main.c:(.text+0x1b3): undefined reference to `glutKeyboardFunc' 
main.c:(.text+0x1c4): undefined reference to `glClearColor' 
main.c:(.text+0x1d1): undefined reference to `glClearDepth' 
main.c:(.text+0x1db): undefined reference to `glDisable' 
main.c:(.text+0x1e5): undefined reference to `glEnable' 
main.c:(.text+0x1ef): undefined reference to `glDepthFunc' 
main.c:(.text+0x1f9): undefined reference to `glEnable' 
main.c:(.text+0x203): undefined reference to `glFrontFace' 
main.c:(.text+0x20d): undefined reference to `glCullFace' 
main.c:(.text+0x217): undefined reference to `glMatrixMode' 
main.c:(.text+0x21c): undefined reference to `glLoadIdentity' 
main.c:(.text+0x25c): undefined reference to `glMatrixMode' 
main.c:(.text+0x266): undefined reference to `glutMainLoop' 
scene.o: In function `createCylinder': 
scene.c:(.text+0xf6): undefined reference to `cosf' 
scene.c:(.text+0x147): undefined reference to `sinf' 
scene.c:(.text+0x179): undefined reference to `cosf' 
scene.c:(.text+0x1ca): undefined reference to `sinf' 
scene.c:(.text+0x201): undefined reference to `cosf' 
scene.c:(.text+0x252): undefined reference to `sinf' 
scene.c:(.text+0x31b): undefined reference to `glGenBuffers' 
scene.c:(.text+0x332): undefined reference to `glBindBuffer' 
scene.c:(.text+0x358): undefined reference to `glBufferData' 
scene.c:(.text+0x36e): undefined reference to `glEnableClientState' 
scene.c:(.text+0x378): undefined reference to `glEnableClientState' 
scene.c:(.text+0x394): undefined reference to `glVertexPointer' 
scene.c:(.text+0x3ab): undefined reference to `glNormalPointer' 
scene.o: In function `sceneInit': 
scene.c:(.text+0x3c4): undefined reference to `glCreateProgram' 
scene.c:(.text+0x40a): undefined reference to `glLinkProgram' 
scene.c:(.text+0x425): undefined reference to `glGetProgramiv' 
scene.c:(.text+0x44b): undefined reference to `glGetProgramiv' 
scene.c:(.text+0x479): undefined reference to `glGetProgramInfoLog' 
scene.c:(.text+0x4b4): undefined reference to `glDeleteProgram' 
scene.c:(.text+0x4d5): undefined reference to `glGetUniformLocation' 
scene.c:(.text+0x4f2): undefined reference to `glGetUniformLocation' 
scene.c:(.text+0x50f): undefined reference to `glGetUniformLocation' 
scene.c:(.text+0x5c5): undefined reference to `glLoadIdentity' 
scene.c:(.text+0x606): undefined reference to `glTranslatef' 
scene.o: In function `sceneRender': 
scene.c:(.text+0x61a): undefined reference to `glClear' 
scene.c:(.text+0x62c): undefined reference to `glUseProgram' 
scene.c:(.text+0x648): undefined reference to `glUniform3fv' 
scene.c:(.text+0x664): undefined reference to `glUniform3fv' 
scene.c:(.text+0x680): undefined reference to `glUniform3fv' 
scene.c:(.text+0x697): undefined reference to `glDrawArrays' 
scene.c:(.text+0x6a6): undefined reference to `glUseProgram' 
scene.c:(.text+0x6b7): undefined reference to `glPushMatrix' 
scene.c:(.text+0x710): undefined reference to `glTranslatef' 
scene.c:(.text+0x731): undefined reference to `glColor3fv' 
scene.c:(.text+0x753): undefined reference to `glutSolidSphere' 
scene.c:(.text+0x758): undefined reference to `glPopMatrix' 
scene.c:(.text+0x76b): undefined reference to `glutSwapBuffers' 
scene.o: In function `sceneCycle': 
scene.c:(.text+0x8c4): undefined reference to `cosf' 
scene.c:(.text+0x8f1): undefined reference to `cosf' 
scene.c:(.text+0x906): undefined reference to `sinf' 
scene.c:(.text+0x933): undefined reference to `sinf' 
scene.c:(.text+0x957): undefined reference to `glutPostRedisplay' 
shader.o: In function `shaderCompileFromFile': 
shader.c:(.text+0x213): undefined reference to `glCreateShader' 
shader.c:(.text+0x241): undefined reference to `glShaderSource' 
shader.c:(.text+0x250): undefined reference to `glCompileShader' 
shader.c:(.text+0x274): undefined reference to `glGetShaderiv' 
shader.c:(.text+0x297): undefined reference to `glGetShaderiv' 
shader.c:(.text+0x2c2): undefined reference to `glGetShaderInfoLog' 
shader.c:(.text+0x2fe): undefined reference to `glDeleteShader' 
shader.o: In function `shaderAttachFromFile': 
shader.c:(.text+0x34a): undefined reference to `glAttachShader' 
shader.c:(.text+0x359): undefined reference to `glDeleteShader' 
collect2: error: ld returned 1 exit status 

我有过剩和台面安装并阅读了一些其他问题，你应该按照makefile的顺序来处理一些问题，但是在这种情况下应该如何？

Answer 1

你需要把$(LDFLAGS)（库）的（对象）的文件名之后，像

$(CC) $(OBJS) -o glsl_lighting $(LDFLAGS) 

按照该online gcc manual的链接选项

[...] It makes a difference where in the command you write this option; the linker searches and processes libraries and object files in the order they are specified. Thus, foo.o -lz bar.o searches library z after file foo.o but before bar.o . If bar.o refers to functions in z , those functions may not be loaded.

因此，目标文件，使用库函数应该出现在库本身之前。