Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Sat, 4 Oct 2008 10:25:37 -0500

The input string is a zero-length string, which is OK, but the char
*value pointer is NULL for some reason, so when it tries to copy \0 to
value[0] you are getting an access violation.  I don't know why
value=NULL.

Mark

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Silver
Sent: Saturday, October 04, 2008 10:18 AM
To: tech-talk
Subject: Re: RE: problem of using Streamdevice

hi, Mark:

  Following is gdb message, could you give me some hints?

Core was generated by `O.linux-x86/streamApp example.cmd'.
Program terminated with signal 11, Segmentation fault.
#0  StdStringConverter::scanString (this=0x9268b8, fmt=@0xb7f6aa14,
input=0x88d2deb "", value=0x0, maxlen=0)
    at ../StreamFormatConverter.cc:281
281             value[0] = '\0';
(gdb) bt
#0  StdStringConverter::scanString (this=0x9268b8, fmt=@0xb7f6aa14,
input=0x88d2deb "", value=0x0, maxlen=0)
    at ../StreamFormatConverter.cc:281
#1  0x00913ce0 in StreamCore::matchInput (this=0x88d29e0) at
../StreamCore.cc:1153
#2  0x00916667 in StreamCore::readCallback (this=0x88d29e0,
status=StreamIoEnd, input=0x88d384c, size=7) at ../StreamCore.cc:1058
#3  0x008ffc6b in AsynDriverInterface::readHandler (this=0x88d37d8) at
../StreamBusInterface.h:112
#4  0x0090100a in handleRequest (pasynUser=0x88ce90c) at
../AsynDriverInterface.cc:1304
#5  0x009509d3 in portThread (pport=0x888fb68) at
../../asyn/asynDriver/asynManager.c:779
#6  0x0064783f in start_routine (arg=0x88ce590) at
../../../src/libCom/osi/os/posix/osdThread.c:320
#7  0x0084b322 in start_thread () from
/lib/i686/nosegneg/libpthread.so.0
#8  0x0028a9ce in clone () from /lib/i686/nosegneg/libc.so.6
(gdb)   

here is some parts of StreamFormatConverter.cc:
int StdStringConverter::

scanString(const StreamFormat& fmt, const char* input,

    char* value, size_t maxlen)

{

    int length = -1;

    if (*input == '\0')

    {

        // match empty string

        value[0] = '\0';

        return 0;

    }

    if (fmt.flags & skip_flag)

    {

        /* can't use return value on vxWorks: sscanf with %* format

           returns -1 at end of string whether value is found or not */

        sscanf(input, fmt.info, &length);

    }

======= At 2008-10-04, 20:04:51 you wrote: =======

>You should enable core dumps and then run gdb on the core file to see
where it crashed.
>
>________________________________
>
>From: [email protected] on behalf of Silver
>Sent: Sat 10/4/2008 6:31 AM
>To: tech-talk
>Subject: problem of using Streamdevice
>
>
>
>hi, all:
>
>  I am just trying Streamdevice driver by Franksen's suggestion. Seems
it's a flexabile way of controlling our equipment. But I met some
problems, the ioc will crash quickly after starting.
>our streamdevice will response 8 bytes data in hex like "55 40 04 67 39
47 be e3". in the data, "67 39 47 be" is a float's 4 bytes. other bytes
are header or crc. So I write my protocol file like this:
># example stream protocol file
>
>#Terminator = CR LF;
>ReplyTimeout = 80000; # 10 sec is very long, for keyboard input
>ReadTimeout = 1000;   # also long for keyboard input
>
># note the field access
>ai {
>    out 170 129 00 129;
>    in "%*3c%#R%*1c";  
>}
>
>my example.db is like this:
># process this record to reload all stream protocols
>
>record (ai, "$(PREFIX):ai")
>{
>    field (DESC, "An analog value")
>    field (DTYP, "stream")
>    field (INP,  "@example.proto ai terminal")
>#    field (PREC, "3")
>#    field (LINR, "LINEAR")
>#    field (ESLO, "0.000305180437934") # 20.0 / 0xffff
>#    field (EOFF, "-10")
>#    field (EGU,  "V")
>    field (SCAN, ".5 second")
>}
>
>my example.cmd file:
>#!./streamApp
>
>dbLoadDatabase "O.Common/streamApp.dbd"
>streamApp_registerRecordDeviceDriver
>
>#where can protocols be located?
>epicsEnvSet "STREAM_PROTOCOL_PATH", ".:protocols:../protocols/"
>
>#setup the busses
>
>#example telnet style IP port setup
>drvAsynIPPortConfigure "terminal", "192.168.1.103:4001"
>#asynOctetSetInputEos "terminal",0,"\r\n"
>#asynOctetSetOutputEos "terminal",0,"\r\n"
>
>#example VXI11 (GPIB via IP) port setup
>#vxi11Configure "GPIB","ins023",1,5.0,"hpib"
>
>#load the records
>dbLoadRecords "example.db","PREFIX=DZ"
>#dbLoadRecords "scalcout.db","PREFIX=DZ"
>
>#lots! of debug output
>#var streamDebug 1
>
>#enable debug output
>var streamDebug 1
>
>iocInit
>
>my output of running ioc:
>
>~/testApp/StreamDevice-2-4/streamApp>./example.cmd
>#!./streamApp
>dbLoadDatabase "O.Common/streamApp.dbd"
>streamApp_registerRecordDeviceDriver
>#where can protocols be located?
>epicsEnvSet "STREAM_PROTOCOL_PATH", ".:protocols:../protocols/"
>#setup the busses
>#example telnet style IP port setup
>drvAsynIPPortConfigure "terminal", "192.168.1.103:4001"
>#asynOctetSetInputEos "terminal",0,"\r\n"
>#asynOctetSetOutputEos "terminal",0,"\r\n"
>#example VXI11 (GPIB via IP) port setup
>#vxi11Configure "GPIB","ins023",1,5.0,"hpib"
>#load the records
>dbLoadRecords "example.db","PREFIX=DZ"
>#dbLoadRecords "scalcout.db","PREFIX=DZ"
>#lots! of debug output
>#var streamDebug 1
>iocInit
>Starting iocInit
>#######################################################################
#####
>###  EPICS IOC CORE built on Sep 27 2008
>###  EPICS R3.14.8.2 $R3-14-8-2$ $2006/01/06 15:55:13$
>#######################################################################
#####
>iocInit: All initialization complete
>#enable debug output
>var streamDebug 1
>epics>
>epics> dbpr DZ:ai
>ASG:                DESC: An analog value                   DISA: 0

>DISP: 0             DISV: 1             NAME: DZ:ai         RVAL: 0

>SEVR: NO_ALARM      STAT: NO_ALARM      SVAL: 0             TPRO: 0

>VAL: 0.003662109375
>epics> Segmentation fault
>:~/testApp/StreamDevice-2-4/streamApp>
>
>Can anybody give me some hints? thanks a lot for your help.
>
>Best regards
>Geyang  2008-10-04

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

Best regards				 
Geyang 2008-10-04

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System