Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uwm.edu!linac!att!att!cbnewsk!barton
From: barton@cbnewsk.att.com (jim.m.barton)
Newsgroups: comp.databases
Subject: Re: Informix messages in ESQL/C
Summary: use rgetmsg() sql library function
Message-ID: <1991Mar14.222941.3459@cbnewsk.att.com>
Date: 14 Mar 91 22:29:41 GMT
References: <1991Mar13.171305.16997@vision.uucp>
Organization: AT&T Bell Laboratories
Lines: 43

In article <1991Mar13.171305.16997@vision.uucp>, chris@vision.uucp (Chris Davies) writes:
> WRT Informix databases, at least version 2, probably OnLine/version 4 too...
> 
> I have an application written with Informix's ESQL/C embedded SQL in C (not
> the 4GL product).  When an error occurs, the error number can be found from
> the sqlca structure (in sqlca.sqlcode).  What I would like to do is to be
> able to obtain the error text associated with that error number.
> 

There is a function provided in the INFORMIX-provided sql library:

	rgetmsg( code, buf, buffer_length )
	long	code;
	char    *buffer;
	int	buffer_length;


	rgetmsg() will populate a caller-provided character buffer, 'buffer'
        with the error message corresponding with database error code 'code'.
	The maximum length of 'buffer' is passed in as 'buffer_length'.
	 

	Note: be sure that the value of code does not exceed the bounds
	for a short, (even though the argument is a long) - it will result
        in a core dump at least on my system.

 I also was told by INFORMIX support that there was no way to read those
.iem files. I discovered rgetmsg() by disassembling some of the
sql library functions.


There is also a (apparently undocumented) method of getting values
to substitite for format specifications found in  some of the error
messages, (e. g., name of table, to substitute for %s in:

	"The specified table (%s) is not in the database." [db error -206]

When a error message contains a format specification, (%s or %d), you
can get the ASCII string to substitute from sqlca.sqlerrm). I have
only encountered at most one format specification and only %s and %d, but
since this seems to be undocumented, code defensively for the
unexpected, (e. g., check for a valid ASCII string in sqlca.sqlerrm
before attempting to use it).