Experimental Physics and
Industrial Control System

"Jemian, Pete R. via Tech-talk" <[email protected]> · Wed, 2 Oct 2019 07:33:26 +0000

It is common to make soft links from the file with the version number, 
such as:

(base) mintadmin@mint-vm:.../lib/linux-x86_64$ ll libCom*
-r--r--r-- 1 mintadmin mintadmin 4.3M Sep  2 09:55 libCom.a
lrwxrwxrwx 1 mintadmin mintadmin   16 Sep  2 09:55 libCom.so -> 
libCom.so.3.17.5*
-r-xr-xr-x 1 mintadmin mintadmin 2.0M Sep  2 09:55 libCom.so.3.17.5*
(base) mintadmin@mint-vm:.../lib/linux-x86_64$ ll libca.*
-r--r--r-- 1 mintadmin mintadmin 5.7M Sep  2 09:57 libca.a
lrwxrwxrwx 1 mintadmin mintadmin   15 Sep  2 09:57 libca.so -> 
libca.so.4.13.4*
-r-xr-xr-x 1 mintadmin mintadmin 2.7M Sep  2 09:57 libca.so.4.13.4*

When the directory contains more than one version, the soft link should 
link the preferred version.

Hope this helps.

Pete

On 2019-10-01 11:28 PM, 肖麟阁 via Tech-talk wrote:
> Hi,
> 
>      i have tried for many times. i found that the useful libs are not 
> libca.so and libCom.so. i can't work well with the two libs(because it 
> shows that it can't find the lib,even if the libs exist). then i found 
> that the actual libs are "libca.so.3.15.6" and "libCom.so.3.15.6".when i 
> add them to the directory it can build and work well.
> 
>      when the program is running, the console shows:
> 
>      ---
> 
>      searching ...
> **** The executable "caRepeater" couldn't be located
> **** because of errno = "No such file or directory".
> **** You may need to modify your PATH environment variable.
> **** Unable to start "CA Repeater" process.
> some channels not found yet
> reading ...
> some values not received
> Beam current (not found): 6.95269e-310
> Gap          (not found): 2.0737e-317
> 
>      ---
> 
>      i don't find some documents about the caRepeater. i don't konw if i 
> can ignore the error.
> 
> 
> 
>     -----原始邮件-----
>     *发件人:*"Johnson, Andrew N." <[email protected]>
>     *发送时间:*2019-10-01 00:18:18 (星期二)
>     *收件人:* "肖麟阁" <[email protected]>, "[email protected]"
>     <[email protected]>
>     *抄送:*
>     *主题:* Re: write a CA client by API in Eclipse
> 
>     Hi,
> 
>     On 9/30/19 7:33 AM, 肖麟阁 via Tech-talk wrote:
>>     I try to run it, but errors come out like following:
>>
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:43:
>>     undefined reference to `ca_task_initialize'
>>             makefile:29: recipe for target 'testEPICS' failed
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:46:
>>     undefined reference to `ca_search_and_connect'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:50:
>>     undefined reference to `ca_search_and_connect'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:55:
>>     undefined reference to `ca_pend_io'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:88:
>>     undefined reference to `ca_message'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:113:
>>     undefined reference to `ca_array_get'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:117:
>>     undefined reference to `ca_array_get'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:122:
>>     undefined reference to `ca_pend_io'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:144:
>>     undefined reference to `ca_message'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:157:
>>     undefined reference to `ca_state'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:165:
>>     undefined reference to `ca_state'
>>             /home/xlg/eclipse-workspace/testEPICS/Debug/../main.c:169:
>>     undefined reference to `ca_task_exit'
>>             collect2: error: ld returned 1 exit status
>>             make: *** [testEPICS] Error 1
>>             "make all" terminated with exit code 2. Build might be
>>     incomplete.
>>
>     Those error messages are from the linker, you need to tell it to
>     link your program with the two libraries, so assuming you're using
>     your own build script the linker needs the additional parameters
>     '-lCa -lCom' and it might need others telling it where to find those
>     libraries such as '-L/path/to/your/library/directory'
> 
>>         by the way, someone else tell me that i just need libCa.so,
>>     libCom and some .h files to write a CA Client. is that true? 
>     That is true. The EPICS build system provides a common framework
>     that was designed to make building client programs easier, but you
>     are not required to use it.
> 
>     - Andrew
> 
>     -- 
>     Complexity comes for free, Simplicity you have to work for.
> 

-- 
----------------------------------------------------------
Pete R. Jemian, Ph.D.                 <[email protected]>
Beam line Controls and Data Acquisition (BC, aka BCDA)
Advanced Photon Source,    Argonne National Laboratory
Argonne, IL  60439                    630 - 252 - 3189
-----------------------------------------------------------
       Education is the one thing for which people
          are willing to pay yet not receive.
-----------------------------------------------------------

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System