Xbasic

CallResult

Description

Provides detailed information about the result of a function call.

Discussion

The CallResult object provides detailed information about the result of a function call. For objects that can maintain state across calls (such as SQL::Connection or SQL::Socket), functions often return true (.t.) or false (.f.) indicating success or failure. You can interrogate the object for more information by accessing the CallResult property and its members to get a result code, text, and further information specific to the environment for database and communications objects and functions.

Note: Some functions return CallResult directly. This is especially important when the object is shared by multiple threads or, for some other reason, can't "remember" the result of a previous call. A good example of this is INET::Socket::Accept() which returns a CallResult and a socket (as a reference parameter). This function can be called by several threads at once, so returning true or false would not work, as the object's CallResult property may change between the time you return from the call to Accept() and the time you access the CallResult property.

You can use the CallResult object in your own functions and classes to format more complete status information and return it to callers.

Example 

This is the default state of the object.

dim error as CallResult

? error
= Canceled = .F.
Code = 0
Error = .F.
NativeCode = 0
NativeText = ""
ReturnDataValue = <No data returned>
RowsAffected = 0
StackTrace = ""
Success = .T.
Text = "Success"
TextAndStackTrace = ""

Setting the . Code property also sets the .Text property.

error.code = 815

? error
= Canceled = .F.
Code = 815
Error = .T.
NativeCode = 0
NativeText = ""
ReturnDataValue = <No data returned>
RowsAffected = 0
StackTrace = ""
Success = .F.
Text = "Missing function, name or value"
TextAndStackTrace = ""

You may add your own error codes to Alpha5.errors in the reserved range (20000 - 24999).

Properties

CanceledLogical

Indicates whether the user cancelled the operation.

CodeNumeric

An Alpha Anywhere error code.

ErrorLogical

Indicates whether there was an error.

NativeCodeNumeric

Error code from an underlying class.

NativeTextCharacter

Error message from an underlying class.

ReturnDataValueAny Type

Value set by the called function.

RowsAffectedLogical

Number of data table rows affected by a SQL operation.

SuccessLogical

Indicates whether the operation succeeded or failed.

TextCharacter

An error message. This is normally read from Alpha5.errors.

TextAndStackTraceCharacter

 

See Also