Experimental Physics and
Industrial Control System

Touchard Dominique <[email protected]> · Fri, 5 Jun 2015 22:04:24 +0000

Hi Andrew,

I reopen a Thread about tricky behavior of dbloadtemplate which can not translates more 100 macros in one shot.

I have these errors when I start a softIOC

More than dbTemplateMaxVars = 100 macro variables used
Substitution file error.
line 17: 'VANODEMES__FUNCTION'
More than dbTemplateMaxVars = 100 macro variables used
Substitution file error.
line 18: 'TDISMES__FUNCTION'
More than dbTemplateMaxVars = 100 macro variables used
Substitution file error.
line 18: 'DEBEAUDISMES__OFFSET'
More than dbTemplateMaxVars = 100 macro variables used
Substitution file error.
line 18: 'LOCKSTATE__OFFSET'
/admin/spiral2/scripts/bootIOC: line 80: 16751 Erreur de segmentation  ./$IOC_CMD_SCRIPT

I have changed the  value of  dbTemplateMaxVars to 900 in  base/src/dbtools/dbLoadTemplate.y but the value shown in error messages stills to 100.

I am sure I made something wrong, but in earlier EPICS version I remenber having changed the max values inside dbtools  and just having type a "make" to see changes.

What must I do to push changes with this new version of dbtools?

Thanks for your help.

Dominique.

Subject: 	Re: Macros limited (edition ;-)
From: 	Andrew Johnson <[email protected]>
To: 	[email protected]
Cc: 	Touchard Dominique <[email protected]>
Date: 	Fri, 5 Jul 2013 10:39:43 -0500

Hi Dominique,

On 2013-07-05 Dominique Touchard wrote:
> It seems that the number of macros for template substitutions during IOC
> startup is limited to 100. Over, a segmentation fault stop the IOCs.
> 
> Is this number correct? Is there any reason?

I was surprised but you're right, src/dbtools/dbLoadTemplate.y defines 
VAR_MAX_VARS as 100 which sets a limit to the number of variables that 
dbLoadTemplate() can handle.  It also defines VAR_MAX_VAR_STRING as 5000 
setting the maximum size of the "variable=value,..." string which it 
constructs to pass to dbLoadRecords().  In neither case though does it check 
when the storage limit set by those macros gets exceeded, thus causing a 
crash.  This is obviously unacceptable and needs to be fixed in Base.

To get around this limit for a particular application you could do the 
template expansion on the host at build time using the msi (Macro 
Substitution and Include) program which is distributed as an EPICS extension.  
You can also increase the above values in your source code and rebuild base, 
which might be a simpler fix in some circumstances.

I have filed a bug-report for this issue.  If someone feels inclined to look 
at rewriting the dbLoadTemplate() code to remove these limitations please let 
me know.
    https://bugs.launchpad.net/epics-base/+bug/1198234

- Andrew

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System