Makefile 11——支持头文件目录指定

现在，是时候在对应目录放入对应文件了：

 /×    foo.h     */

 #ifndef __FOO_H
 #define __FOO_H

 void foo(void)

 #endif/*__FOO_H*/

 /*    foo.c     */

 #include <stdio.h>
 #include "foo.h"
 void foo(void)
 {
     printf("This is foo()!\n");
 }

 /*     main.c   */

 #include "foo.h"
 int main(void)
 {
     return 0;
 }

执行make后报错：

这是在构建依赖文件时，gcc因为找不到foo.h而报错。那是因为foo.h和foo.c放在不同的目录中，这样需要使用gcc的 -I 选项，指定包含路径，所以，更改后的Makefile如下：

 .PHONY: all clean

 MKDIR = mkdir
 RM = rm
 RMFLAGS =-rf

 CC = gcc
 AR = ar
 ARFLAGS = crs

 DIR_OBJS = objs
 DIR_EXES = $(ROOT)/build/exes
 DIR_DEPS = deps
 DIR_LIBS = $(ROOT)/build/libs
 DIRS = $(DIR_OBJS) $(DIR_EXES) $(DIR_DEPS) $(DIR_LIBS)
 RMS = $(DIR_OBJS) $(DIR_DEPS)

 ifneq ("$(EXE)", "")
 EXE := $(addprefix $(DIR_EXES)/, $(EXE))
 RMS += $(EXE)
 endif

 ifneq ("$(LIB)", "")
 LIB := $(addprefix $(DIR_LIBS)/, $(LIB))
 RMS += $(LIB)
 endif

 SRCS = $(wildcard *.c)
 OBJS = $(SRCS:.c=.o)
 OBJS := $(addprefix $(DIR_OBJS)/, $(OBJS))
 DEPS = $(SRCS:.c=.dep)
 DEPS := $(addprefix $(DIR_DEPS)/, $(DEPS))

 ifeq ("$(wildcard $(DIR_OBJS))", "")
 DEP_DIR_OBJS := $(DIR_OBJS)
 endif
 ifeq ("$(wildcard $(DIR_EXES))", "")
 DEP_DIR_EXES := $(DIR_EXES)
 endif
 ifeq ("$(wildcard $(DIR_DEPS))", "")
 DEP_DIR_DEPS := $(DIR_DEPS)
 endif
 ifeq ("$(wildcard $(DIR_LIBS))", "")
 DEP_DIR_LIBS := $(DIR_LIBS)
 endif

 all: $(EXE) $(LIB)

 ifneq ($(MAKECMDGOALS), clean)
 include $(DEPS)
 endif

 ifneq ("$(INCLUDE_DIRS)", "")
 INCLUDE_DIRS := $(strip $(INCLUDE_DIRS))
 INCLUDE_DIRS := $(addprefix -I, $(INCLUDE_DIRS))
 endif

 $(DIRS):
     $(MKDIR) $@
 $(EXE): $(DEP_DIR_EXES) $(OBJS)
     $(CC) -o $@ $(filter %.o, $^)
 $(LIB): $(DEP_DIR_LIBS) $(OBJS)
     $(AR) $(ARFLAGS) $@ $(filter %.o, $^)
 $(DIR_OBJS)/%.o: $(DEP_DIR_OBJS) %.c
     $(CC) $(INCLUDE_DIRS) -o $@ -c $(filter %.c, $^)
 $(DIR_DEPS)/%.dep: $(DEP_DIR_DEPS) %.c
     @echo "Creating $@ ..."
     @set -e ; \
     $(RM) $(RMFLAGS) $@.tmp ; \
     $(CC) $(INCLUDE_DIRS) -E -MM $(filter %.c, $^) > $@.tmp ; \
     sed 's,\(.*\)\.o[ :]*,objs/\1.o $@: ,g' < $@.tmp > $@ ; \
     $(RM) $(RMFLAGS) $@.tmp
 clean:
     $(RM) $(RMFLAGS) $(RMS)

这样就完成了支持头文件目录指定