Re: Check existence of data area in ILE C

Very nice.
_CTLA_HANDLE_NO_MSG made the trick!!

Many thanks,

Zvi

On 10/03/2015 17:36, CRPence wrote:

On 10-Mar-2015 10:20 -0500, Zvi Kave wrote:

Sorry. It is too much complicated for me.
Waiting for simpler solution.
Perhaps a change in the exception handler?:
#pragma exception_handler(ERROR_OCCURED, ca, 0, _C2_MH_ESCAPE, \
_CTLA_HANDLE, "MCH3401")

Of course that would not resolve the issue of concurrency introduced
by performing a separate /check for existence/ test prior to invoking
the request to /Retrieve Data Area/ that itself performs the same
existence check. Nevertheless...

I was unaware that the capability to suppress the messaging was
exposed externally in any of the HLLs, but a quick search of the
KnowledgeCenter revealed that there are both of the Exception Control
Actions available to the C language, "_CTLA_IGNORE_NO_MSG" and
"_CTLA_HANDLE_NO_MSG", which apparently provide the equivalent effect of
the message suppression:
[1]<http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/rzarf/prag_exception_handler.htm%23prag_exception_handler>
"...
ctl_action

Specifies an integer constant to indicate what action should take
place for this exception handler. If handler is a function, the default
value is _CTLA_INVOKE. If handler is a label, the default value is
_CTLA_HANDLE. This parameter is optional.

The following are valid exception control actions that are defined
in the <except.h> header file:

#define name Defined value and action
...
_CTLA_HANDLE_NO_MSG Defined to 3. The exception is handled but
messages are not logged before calling the handler. The exception will
no longer be active when the handler gets control. Exception messages
are not logged. Msg_Ref_Key in the typedef _INTRPT_Hndlr_Parms_T is set
to zero. Exception processing ends when the exception handler returns.
This is valid for functions and labels.
...
_CTLA_IGNORE_NO_MSG Defined to 132. The exception is handled and
messages are not logged. Control is not passed to the handler function
named on the directive and exception will no longer be active. Execution
resumes at the instruction immediately following the instruction that
caused the exception. This is valid for functions only.
..."

References

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1. http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/rzarf/prag_exception_handler.htm%23prag_exception_handler