如何避免我的makefile重新链接 [英] How to avoid my makefile to relink

问题描述

我的Makefile正在重新链接，我找不到原因.

My Makefile is relinking and I can't find why.

我不确定为什么malloc假定必须执行$(NAME). $(SRC:.c = .o)宏会更改.o文件的时间戳还是类似的内容?

I'm not sure why malloc assume that $(NAME) have to be executed. Is the $(SRC:.c=.o) macro changing the timestamps of the .o files or something like that ?

CC               = gcc
NAME             = app

#

CFLAGS           = -Wall -Werror -Wextra -pedantic -pedantic-errors
INCLUDES         = -I ./includes

#

DIRSRC           = srcs/
DIROBJ           = objs/

SRC             += main.c
SRC             += malloc.c

OBJ              = $(SRC:.c=.o)
DIROBJS          = $(addprefix $(DIROBJ), $(OBJ))

#

LIBS_PATH        = ./libs

LIBFT_PATH       = $(LIBS_PATH)/libft
LIBFT_INCLUDES   = -I $(LIBFT_PATH)
LIBFT            = -L $(LIBFT_PATH) -lft

#

COMPILE          = $(CC) $(CFLAGS) $(INCLUDES)

#

all: $(NAME)

$(NAME): configure libs $(DIROBJS)
    $(COMPILE) $(LIBFT) $(DIROBJS) -o $(NAME)

$(DIROBJ)%.o: $(DIRSRC)%.c
    @echo Compiling: $<
    $(COMPILE) $(LIBS_INCLUDES) -c $< -o $@

clean:
    @rm -rf $(DIROBJ)

fclean: clean
    @rm -rf $(NAME)

re: fclean all

#

configure:
    @mkdir -p $(DIROBJ)

#

libs:
    @$(MAKE) -C $(LIBS)

.PHONY: all configure clean fclean re libs cleanlibs fcleanlibs relibs

推荐答案

@rtur的答案有效，但是我应该提到另一种方法.您可以这样做:

@rtur's answer works, however I should mention another alternative. You could do:

$(DIROBJ):
    mkdir $@

$(DIROBJ)/%.o: $(DIRSRC)/%.c | $(DIROBJ)
     @echo Compiling: $<
     $(COMPILE) $(LIBS_INCLUDES) -c $< -o $@

这样，仅当目录不存在时才创建目录.要注意的一件事是|符号.这使$(DIROBJ)成为仅订购的先决条件.这意味着，如果它比目标新，则不会导致目标重建.这对于目录确实非常重要，因为目录的时间戳记是目录中最后一项的添加/删除/修改的日期，并且如果没有该符号，您的目标将始终过期.这被认为是更干净的，因为这样您对mkdir的调用较少.

That way, it only makes the directory if it doesn't already exist. One thing to notice is the | symbol. This makes $(DIROBJ) an order-only prerequisite. This means if it's newer than the target, it will not cause the the target to rebuild. This is really important for directories, as the timestamp of a directory is the date the last item in it was added/deleted/modified, and your target would always be out of date without that symbol. This is considered cleaner, as you have less invocations of mkdir this way.

此外，作为样式说明，通常，您不会在目录名称的末尾包括结尾的/. $(OBJ_DIR)/%.o看起来比$(OBJ_DIR)%.o好.当然，那可能只是我的意见:-)

Also, as a style note, you usually, you don't include the trailing / at the end of directory names. $(OBJ_DIR)/%.o looks nicer than $(OBJ_DIR)%.o. Of course, that could just be my opinion :-)

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