问题描述
面临的问题可能难以解释和理解，因为给出整个图片会太大而又困难.
Am facing a problem that may be slightly complicated to explain and understand as giving the entire picture would be too big and difficult.
请原谅我.
考虑以下Makefile:
Consider the following Makefile:
all: clients.so simulator backup
LD_PRELOAD=/home/Juggler/client/clients.so ./simulator
backup: backup.c libclient.a
gcc backup.c -o backup -L /home/Juggler/client -L. -lclient -ldl
simulator: simulator.c libclient.a
gcc -g simulator.c -o simulator -L /home/Juggler/client -L. -lclient -ldl -pthread
libclient.a: libclient.o client.o
ar rcs libclient.a libclient.o client.o
libclient.o:libclient.c
gcc -c libclient.c -o libclient.o -pthread
clients.so: client.o client_invoke.o
ld -shared -o clients.so client_invoke.o client.o -ldl
client_invoke.o: client_invoke.c
gcc -Wall -fPIC -DPIC -c -g client_invoke.c
client.o: client.c
gcc -Wall -fPIC -DPIC -c -g client.c -ldl -pthread
我们从libclient.c中调用用client.c编写的函数，而client.c中的这些函数调用pthread_key_create()，pthread_setspecific..etc.
We call function written in client.c from libclient.c and these functions in client.c make call to pthread_key_create(), pthread_setspecific..etc.
线程是由Simulator.c创建的，这些线程访问其他文件中编写的函数.
Threads are created by simulator.c and theses threads access functions written in he other files.
在执行...时，出现类似以下的错误.
On doing make...Errors like the following appear.
/home/Juggler/client/libclient.a(client.o):In function 'setup_connection':
/home/Juggler/client/client.c:35: undefined reference to 'pthread_setspecific'
pthread.h已包含在client.c和libclient.c
pthread.h has been included in both client.c and libclient.c
将感谢任何指针.我了解信息很少...
Would be grateful for anypointers . I understand information is very less...
谢谢
推荐答案
在linux上，pthread函数位于libpthread库中.因此，您必须链接到该页面.
On linux, pthread functions live in the libpthread library. So you have to link to that.
使用pthreads时，正确的方法是使用-pthread进行编译和链接，而cc将链接到pthread库中.对于某些可执行文件，您具有-pthread标志，但对于其他可执行文件却没有，对于clients.so库，没有-pthread标志，因此请在需要的位置添加该标志.
The proper way, when using pthreads, is to compile and link using the -pthread , which, among other things, will link in the pthread library. You have the -pthread flag for some of your executables, but not for others, and not for your clients.so library, so add the flag where required.
另外，请记住，在创建共享库时，应使用-fPIC标志编译源文件.
Also, remember, when you are creating a shared library, you should compile the source files with the -fPIC flag.
(而且，似乎您正在直接调用ld来生成client.so库，您确实应该使用gcc进行链接.)
(And, seems you are calling ld directly to produce the client.so library, you really should use gcc to do the linking.)
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