Re: MDB - Error questions

On 14 Jun 2002, Stig S. Bakken wrote: > On Thu, 2002-06-13 at 17:57, Brent Cook wrote: > > > > Also, what's the difference between doing this: > > > > return PEAR::raiseError(NULL, DB_ERROR_INVALID_DSN, NULL, NULL, 'no valid > > DBMS driver include path specified', 'MDB_Error', TRUE); > > > > and this: > > > > return PEAR::raiseError('no valid DBMS driver include path specified', > > NULL, DB_ERROR_INVALID_DSN, NULL, NULL, 'MDB_Error'); > > The first one has an extra parameter, called "skipmsg" which makes > raiseError skip the error message when creating the error object. > Instead, the error code becomes the first parameter. This feature is > useful when you have abstracted error codes like [M]DB and want to base > error handling on error codes rather than messages. > > - Stig > Hmm.. I guess what I really meant was, it appears that there are two ways to pass a string message; either through the $message field, or through the $userinfo field. I don't understand the difference between the $userinfo field and the $message field. I also don't understand why raiseError can't just see that the first parameter is null and skip it, rather than requiring an extra parameter at the end. According to the docs, $message is a mixed parameter, so it could represent an error code if needed. So why have the $code parameter at all, if $message could be a code? Why have another $userinfo field if there can be a $message field? Would anyone write code that actually expects to read a string $message returned from as error? It seems that in most cases, an error should just return a message and a code. Then, you have a code for fast checking within code, and an error message for the user if you need that too. I understand the parameters currently as: $message - what went wrong (mixed) $code - what went wrong (integer) $userinfo - why it went wrong (string) I haven't really used this function beyond PEAR::raiseError("Oops") because it seems like there are too many of ways to skin a chicken here and it's not clear to me why. Maybe its for backwards compatibility. - Brent