英文:
Makefile cant find libraries
问题
我试图为树莓派4上的paho.mqtt项目编写自己的makefile。
我已经下载并测试了paho.mqtt的安装，一切都按预期运行。
所以我现在正在测试一些C代码，但我只是无法弄清楚makefile（我是新手），我的文件到目前为止如下：
NAME = mqtt_test
OBJ = $(NAME).o
LIBS = -lpaho-mqtt3c -lpaho-mqtt3cs
CFLAGS = -Wall -I/usr/local/include -L/usr/local/lib
CC = gcc
EXTENSION = .c
all: $(NAME)
%.o: %$(EXTENSION)
$(CC) -c -o $@ $< $(CFLAGS)
$(NAME): $(OBJ)
$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
.PHONY: clean
clean:
@rm -f *.o *~ core $(NAME)
这返回：
gcc -o mqtt_test mqtt_test.o -Wall -I/usr/local/include -L/usr/local/lib -lpaho-mqtt3c -lpaho-mqtt3cs
/usr/bin/ld: 无法找到 -lpaho-mqtt3c
/usr/bin/ld: 无法找到 -lpaho-mqtt3cs
collect2: 错误: ld 返回 1
make: *** [makefile:14: mqtt_test] 错误 1
我已经检查了-I和-L标志后面的目录中包含头文件和库文件。
当我查看/usr/bin时，没有ld，但有以paho_为前缀的paho文件，但没有库文件。
我漏掉了什么？
英文:
I'm trying to write my own makefile for a paho.mqtt project on a Raspberry Pi 4.
I've downloaded & tested the paho.mqtt install and its all working as expected.
So I'm now testing some C code but I just cant figure out the makefile (I'm new to this), my file so far,
NAME = mqtt_test
OBJ = $(NAME).o
LIBS = -libpaho-mqtt3c -libpaho-mqtt3cs
CFLAGS = -Wall -I/usr/local/include -L/usr/local/lib
CC = gcc
EXTENSION = .c
all: $(NAME)
%.o: %$(EXTENSION) $(DEPS)
$(CC) -c -o $@ $< $(CFLAGS)
$(NAME): $(OBJ)
$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
.PHONY: clean
clean:
@rm -f *.o *~ core $(NAME)
This returns,
gcc -o mqtt_test mqtt_test.o -Wall -I/usr/local/include -L/usr/local/lib -libpaho-mqtt3c -libpaho-mqtt3cs
/usr/bin/ld: cannot find -libpaho-mqtt3c
/usr/bin/ld: cannot find -libpaho-mqtt3cs
collect2: error: ld returned 1 exit status
make: *** [makefile:14: mqtt_test] Error 1
I've checked & the includes and libraries are in the directories I put after the-I and -L flags.
When I look in /usr/bin there is no ld but there are paho files prefixed with paho_ but no library files.
What am I missing?
答案1
得分: 2
You don't use -libpaho-mqtt3c (etc.)
The option is -l, so when you write -libpaho-mqtt3c, the linker is looking for libraries named ibpaho-mqtt3c, which of course do not exist. That would be either libibpaho-mqtt3c.a or libibpaho-mqtt3c.so.
You want to use -lpaho-mqtt3c, remove the lib at the front and the extension .a or .so, and add in the option -l.
英文:
You don't use -libpaho-mqtt3c (etc.)
The option is -l so when you write -libpaho-mqtt3c the linker is looking for libraries named ibpaho-mqtt3c which of course do not exist: that would be either libibpaho-mqtt3c.a or libibpaho-mqtt3c.so.
You want to use -lpaho-mqtt3c: remove the lib at the front and the extension .a or .so, and add in the option -l.
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