将多个 C 库链接到 C 创建可执行文件

Question

我正在尝试创建一个依赖于多个 C 静态库的 C 可执行文件。 我有两个图书馆： ../libs/libsulibs.a 和 ../ppm_client/libppm_client.a。 libppm_client.a调用libsulibs.a的部分函数

这是我的 Makefiles

../libs/Makefile

LIBS=-lpthread
CC=gcc
CFLAGS=-Wall -g
INCLUDES=-I .
OBJ=WheelTimer.o threadApi.o LinkedListApi.o
TARGET=libsulibs.a
${TARGET}:$(OBJ)
    ar rs ${TARGET} $(OBJ)
%.o:%.c
     ${CC} ${CFLAGS} -c ${INCLUDES} $<
clean:
    rm *.o
    rm ${TARGET}

我通过这个makefile成功创建了libsulibs.a

../ppm_client/Makefile

CC=gcc
CFLAGS=-Wall -g
INCLUDES=-I . -I ../libs -I ../ppm
OBJ=ppm_pkt_enums.o ppm_client.o ppm_client_sock.o
TARGET=libppm_client.a
${TARGET}:$(OBJ)
    ar rs ${TARGET} ${OBJ}
ppm_pkt_enums.o:ppm_pkt_enums.c
    gcc -g -c ${INCLUDES} ppm_pkt_enums.c -o ppm_pkt_enums.o
ppm_client.o:ppm_client.c
    gcc -g -c ${INCLUDES} ppm_client.c -o ppm_client.o
ppm_client_sock.o:ppm_client_sock.c
    gcc -g -c ${INCLUDES} ppm_client_sock.c -o ppm_client_sock.o
clean:
    rm *.o
    rm ${TARGET}

这个makefile也成功创建了libppm_client.a。

现在，在当前目录中，我有主 Makefile 来创建可执行文件

CC=gcc
CFLAGS=-g -Wall
STANDARD_LIBS=-lpthread
PPM_OBJ=ppm.o ppm_main.o
LIBS_OBJ=libs/LinkedListApi.o libs/threadApi.o libs/WheelTimer.o
PPM_LIBS=../libs/libsulibs.a
PPM_CLIENT_LIBS=../ppm_client/libppm_client.a
INCLUDES=-I . -I ../libs -I ../ppm_client
TARGET:exe ${PPM_LIBS} ${PPM_CLIENT_LIBS}

ppm.o:ppm.c
    gcc -g -c ${INCLUDES} ppm.c -o ppm.o
ppm_main.o:ppm_main.c
    gcc -g -c ${INCLUDES} ppm_main.c -o ppm_main.o

${PPM_LIBS}:
    (cd ../libs; make)
${PPM_CLIENT_LIBS}:
    (cd ../ppm_client; make)
exe:${PPM_LIBS} ${PPM_OBJ} ${STANDARD_LIBS} ${PPM_CLIENT_LIBS}
    ${CC} ${CFLAGS} ${PPM_OBJ} -o exe -L ../libs -lsulibs -L ../ppm_client -lppm_client ${STANDARD_LIBS}
clean:
    rm *.o
    (cd ../libs; make clean)
    (cd ../ppm_client; make clean)
    rm exe

但是当我运行make 时，它以错误结束：undefined reference to pthread_init。 pthread_init 是libsulibs.a 中定义的函数，依赖于标准pthread 库。

vm@vm:~/Documents/PeriodicPacketManager/ppm$ make
(cd ../libs; make)
make[1]: Entering directory `/home/vm/Documents/PeriodicPacketManager/libs'
gcc -Wall -g -c -I . WheelTimer.c
gcc -Wall -g -c -I . threadApi.c
gcc -Wall -g -c -I . LinkedListApi.c
ar rs libsulibs.a WheelTimer.o threadApi.o LinkedListApi.o
ar: creating libsulibs.a
make[1]: Leaving directory `/home/vm/Documents/PeriodicPacketManager/libs'
gcc -g -c -I . -I ../libs -I ../ppm_client ppm.c -o ppm.o
gcc -g -c -I . -I ../libs -I ../ppm_client ppm_main.c -o ppm_main.o
(cd ../ppm_client; make)
make[1]: Entering directory `/home/vm/Documents/PeriodicPacketManager/ppm_client'
gcc -g -c -I . -I ../libs -I ../ppm ppm_pkt_enums.c -o ppm_pkt_enums.o
gcc -g -c -I . -I ../libs -I ../ppm ppm_client.c -o ppm_client.o
gcc -g -c -I . -I ../libs -I ../ppm ppm_client_sock.c -o ppm_client_sock.o
ar rs libppm_client.a ppm_pkt_enums.o ppm_client.o ppm_client_sock.o
ar: creating libppm_client.a
make[1]: Leaving directory `/home/vm/Documents/PeriodicPacketManager/ppm_client'
gcc -g -Wall ppm.o ppm_main.o -o exe -L ../libs -lsulibs -L ../ppm_client -lppm_client -lpthread
../ppm_client/libppm_client.a(ppm_client_sock.o): In function `ppm_client_init_socket':
/home/vm/Documents/PeriodicPacketManager/ppm_client/ppm_client_sock.c:138: undefined reference to `pthread_init'
collect2: error: ld returned 1 exit status
make: *** [exe] Error 1

请帮助我在这里缺少什么。

Answer 1

哇！

@Antti Haapalam

更改库的工作顺序。

在 Main Makefile 中，我更改了顺序：

${CC} ${CFLAGS} ${PPM_OBJ} -o exe -L ../libs -lsulibs -L ../ppm_client -lppm_client ${STANDARD_LIBS}

收件人：

${CC} ${CFLAGS} ${PPM_OBJ} -o exe -L ../ppm_client -lppm_client -L ../libs -lsulibs ${STANDARD_LIBS}

任何人都可以评论推理吗？