经常会用写一些小的程序有的是作为测试，但是每次都需要写一些简单的GCC 命令，有的时候移植一些项目中的部分代码到小程序里面进行测试，这个时候GCC 命令并不好些，如果写啦一个比较常用的makefile的模板，然后把文件添加进来，简单的修改一下makefile即可以完成测试任务何乐而不为。
源代码有三个文件，三个文件在同一个目录下面/hellomake
hellomake .c:#include "hellofunc.h"#include#include int main() { // call a function in another file myPrintHelloMake(); double value =15; printf("Value:%f\n",log(value)); return(0);}
hellofunc.c:
#include "hellofunc.h"#includevoid myPrintHelloMake(void) { printf("Hello makefiles!\n"); return;}
hellofunc.h
/*example include file*/void myPrintHelloMake(void);
编译，执行gcc 命令如下：
gcc -Wall -o hellomake hellomake.c hellofunc.c -lm
编译生成可执行文件hellomake.
执行命令："./hellomake",结果如下：
Hello makefiles!Value:2.708050
gcc 的命令执行顺序应该编译源文件生成目标文件，然后链接目标文件生成可执行文件，执行命令如下：
gcc -Wall -c hellomake.c hellofunc.cgcc -o hellomake hellomake.o hellofunc.o -lm
gcc -Wall -o hellofunc.o hellofunc.c
gcc -Wall -o hellomake.o hellomake.c
在当前目录下添加makefile文件：
#Hellomake#Magnum， 2014-10-19# 指令编译器和选项 CC=gcc CFLAGS=-Wall LIBS=-lm # 目标文件 TARGET=hellomakeSRCS = hellofunc.c \ hellomake.c # 依赖目标 OBJS =$(SRCS:.c=.o)$(TARGET):$(OBJS) #@echo TARGET:$(OBJS) # @echo OBJECTS:$^ $(CC) -o $@ $^ $(LIBS)clean: rm -rf $(TARGET) $(OBJS) $(OBJS):$(SRCS) $(CC) $(CFLAGS) -o $@ -c $<
执行make,报错：
gcc -Wall -o hellofunc.o -c hellofunc.cgcc -Wall -o hellomake.o -c hellofunc.cgcc -o hellomake hellofunc.o hellomake.o -lmhellomake.o: In function `myPrintHelloMake':hellofunc.c:(.text+0x0): multiple definition of `myPrintHelloMake'hellofunc.o:hellofunc.c:(.text+0x0): first defined here/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 0 has invalid symbol index 10/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 1 has invalid symbol index 11/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 2 has invalid symbol index 2/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 3 has invalid symbol index 2/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 4 has invalid symbol index 10/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 5 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 6 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 7 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 8 has invalid symbol index 2/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 9 has invalid symbol index 2/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 10 has invalid symbol index 11/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 11 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 12 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 13 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 14 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 15 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 16 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 17 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 18 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 19 has invalid symbol index 12/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 20 has invalid symbol index 19/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o: In function `_start':(.text+0x20): undefined reference to `main'collect2: ld returned 1 exit statusmake: *** [hellomake] Error 1
错自第二句：
gcc -Wall -o hellomake.o -c hellofunc.c
使用$(OBJS):$(SRCS)并不会自动推进，修改makefile文件：
#Hellomake#Magnum， 2014-10-19# 指令编译器和选项 CC=gcc CFLAGS=-Wall LIBS=-lm # 目标文件 TARGET=hellomakeSRCS = hellofunc.c \ hellomake.c # 依赖目标 OBJS =$(SRCS:.c=.o)$(TARGET):$(OBJS) # @echo TARGET:$(OBJS) # @echo OBJECTS:$^ $(CC) -o $@ $^ $(LIBS) #$@指目标文件，这里是hellomake,$^指所有依赖文件，这里指hellofunc.o,hellomake.oclean: rm -rf $(TARGET) $(OBJS) %.o:%.c $(CC) $(CFLAGS) -o $@ -c $< #$
执行make,编译OK。
如果有更多的源文件，一个个加很麻烦，可以用wildcard 来解决这个问题，进一步版本的makefile如下：
#Hellomake#Magnum， 2014-10-19# 指令编译器和选项 CC=gcc CFLAGS=-Wall LIBS=-lm # 目标文件 TARGET=hellomakeSRCS = $(wildcard *.c) #当前文件夹下面的所有.c文件#SRCS = hellofunc.c \# hellomake.c # 依赖目标 OBJS =$(SRCS:.c=.o) #$(TARGET):$(OBJS) # @echo TARGET:$(OBJS) # @echo OBJECTS:$^ $(CC) -o $@ $^ $(LIBS) #$@指目标文件，这里是hellomake,$^指所有依赖文件，这里指hellofunc.o,hellomake.oclean: rm -rf $(TARGET) $(OBJS) %.o:%.c $(CC) $(CFLAGS) -o $@ -c $< #$
这里到这结束，下一篇是跨多个文件夹的makefile 如何编写。