Makefile 错误未找到规则但存在规则

Question

这个 Makefile

CC = gcc

INC_PATH = -I../common/

SOURCEDIR := ./
SOURCES := $(wildcard $(SOURCEDIR)/*.c)
OBJDIR :=./obj
OBJECTS := $(patsubst $(SOURCEDIR)/%.c,$(OBJDIR)/%.o, $(SOURCES))
DEPENDS := $(patsubst $(SOURCEDIR)/%.c,$(OBJDIR)/%.d, $(SOURCES))

COMMONDIR     := ../common
SOURCESCOMMON := $(wildcard $(COMMONDIR)/*.c)
OBJDIRCOMMON  := $(COMMONDIR)/obj
OBJECTSCOMMON := $(patsubst $(COMMONDIR)/%.c,$(OBJDIRCOMMON)/%.o, $(SOURCESCOMMON))
DEPENDSCOMMON := $(patsubst $(COMMONDIR)/%.c,$(OBJDIRCOMMON)/%.d, $(SOURCESCOMMON))

# ADD MORE WARNINGS!
WARNING := -Wall -Wextra

# OBJS_LOC is in current working directory,
EXECUTABLE := ../server
# .PHONY means these rules get executed even if
# files of those names exist.
.PHONY: all clean

# The first rule is the default, ie. "make",
# "make all" and "make parking" mean the same
all: $(EXECUTABLE)

clean:
    $(RM) $(OBJECTS) $(DEPENDS) $(EXECUTABLE)

# Linking the executable from the object files
# $^   # "src.c src.h" (all prerequisites)
$(EXECUTABLE): $(OBJECTSCOMMON) $(OBJECTS)
    $(CC) $(WARNING) $^ -o $@

-include $(DEPENDS) $(DEPENDSCOMMON)

$(OBJDIR):
    mkdir -p $(OBJDIR)

$(OBJDIR)/%.o: $(SOURCEDIR)/%.c Makefile | $(OBJDIR)
    $(CC) $(WARNING) -MMD -MP -c $(INC_PATH) $< -o $@

$(OBJDIRCOMMON):
    mkdir -p $(OBJDIRCOMMON)

$(OBJDIRCOMMON)/%.o: $(SOURCESCOMMON)/%.c | $(OBJDIRCOMMON)
    $(CC) $(WARNING) -MMD -MP -c $< -o $@

正在生成错误：

 make[1]: *** No rule to make target '../common/obj/utilities.o', needed by '../server'.  Stop.

生成规则的主要规则的输入 $(OBJECTSCOMMON) 引用目录 OBJDIRCOMMON 中包含的对象文件 *.o。生成此对象的规则没有明确的目标，但它是：

$(OBJDIRCOMMON)/%.o: $(SOURCESCOMMON)/%.c | $(OBJDIRCOMMON)
    $(CC) $(WARNING) -MMD -MP -c $< -o $@

我认为这是产生错误的原因。我期待定义 OBJECTSCOMMON := $(patsubst $(COMMONDIR)/%.c,$(OBJDIRCOMMON)/%.o, $(SOURCESCOMMON)) 制定规则并有效生成 $()

然而，类似的规则用于在同一个 Makefile 中生成 $(OBJECTS) 并且它正在工作：

$(OBJDIR)/%.o: $(SOURCEDIR)/%.c Makefile | $(OBJDIR)
    $(CC) $(WARNING) -MMD -MP -c $(INC_PATH) $< -o $@

那么为什么规则之间的行为不同？

Answer 1

$(SOURCESCOMMON)/%.c 扩展为 $(wildcard $(COMMONDIR)/*.c)/%.c，因此该模式将包含类似 ../common/utilities.c/%.c 的内容（可能具有不同的文件名）。此文件不存在，因此忽略模式规则。

其他规则使用$(SOURCEDIR)，所以没有这个问题。

Makefile 错误未找到规则但存在规则

Makefile error no rule found but rule is present

makefile

compilation

object-files