Hi,

I am running client-server program for shared memory.

When I compile.
gcc -o server_shm server_shm.c

like this...
I am getting this errors:
================================================
/tmp/cccuk2D3.o(.text+0x4a): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0x7e): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0x90): In function `main':
: undefined reference to `sem_create'
/tmp/cccuk2D3.o(.text+0xae): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0xc0): In function `main':
: undefined reference to `sem_create'
/tmp/cccuk2D3.o(.text+0xde): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0x112): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0x145): In function `main':
: undefined reference to `err_sys'
/tmp/cccuk2D3.o(.text+0x156): In function `main':
: undefined reference to `sem_close'
/tmp/cccuk2D3.o(.text+0x167): In function `main':
: undefined reference to `sem_close'
/tmp/cccuk2D3.o(.text+0x189): In function `server':
: undefined reference to `sema_wait'
/tmp/cccuk2D3.o(.text+0x1d9): In function `server':
: undefined reference to `sys_err_str'
/tmp/cccuk2D3.o(.text+0x237): In function `server':
: undefined reference to `sem_signal'
/tmp/cccuk2D3.o(.text+0x24: In function `server':
: undefined reference to `sem_wait'
/tmp/cccuk2D3.o(.text+0x28f): In function `server':
: undefined reference to `sem_signal'
/tmp/cccuk2D3.o(.text+0x2a0): In function `server':
: undefined reference to `sem_wait'
/tmp/cccuk2D3.o(.text+0x2ec): In function `server':
: undefined reference to `sem_signal'
collect2: ld returned 1 exit status

===================================================


Can anyone help me regarding this....

Who defines these functions? Are they ones that you wrote? Are they in a "helper" .c file that you compiled separately? What?

• err_sys()
• sys_err_str()
• sem_create()
• sem_close()
• sem_wait()
• sema_wait()
• sem_signal()

* err_sys()
* sys_err_str()
* sem_create()
* sem_close()
* sem_wait()
* sema_wait()
* sem_signal()
These system calls are defined in different header files like sys/shm.h,sys/ipc.h

And I already included.
But I am getting this strange result when I am compiling.
I think,this is the compiler problem.So I need to reinstall the gcc ? or upgrade it?

can any one give me the hint??????

I could be wrong, but I'm thinking that you might be gathering different semaphore-handling functions from different sets of such functions.

My advice (which may be worthless) is that you pick one set of such semaphore-handling functions and remain with that set. You can find one such set by doing:

You can find another such set by doing:

It doesn't sound like this is answering your questions, but I suspect that if you follow this advice, your problem will disappear.

Semaphores can be tricky. If your program blows up, often you have extra semaphores lying around which no one is using. So I'd go with (and have gone with) file record locking instead.

Hope this helps a little.