Err

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Err

Returns the number of the last runtime error, or sets it without jumping.

Description

The Err() function returns the FreeBASIC run-time error number (a 32 bit Long) which can be set by the built-in statements and functions, or by the program through Err = number or Error. Unlike Error, Err = number sets the error number without invoking an error handler.

See Runtime Error Codes for a listing of the predefined runtime error numbers and their associated meaning. The program may use additional custom error numbers.

Err can always be used, even if QB-like error handling is not enabled.

Note: Care should be taken when calling an internal function (such as Print) after an error occurred, because it will reset the error value with its own error status. To preserve the Err value, it is a good idea to store it in a variable as soon as the error handler is entered.

Remark: Some procedures used in their function version return directly the error code (a 32 bit Long).
That is the case for: BLoad, BSave, Close, FileCopy, GetJoystick, GetMouse, ImageInfo, Kill, Open, Open Com, Open Cons, Open Err, Open Lpt, Open Pipe, Open Scrn, ScreenRes, ScreenSync, SetDate, SetMouse, SetTime.

Remarks

Usage

result = Err( )

or

Err = number

Differences from QB

• Error numbers are not the same as in QB.

See also

• On Error
• Error
• Error Handling

Examples

An example using QBasic style error handling (compile with -ex option)

'' compile with -ex

on error goto error_handler

error 150

end

error_handler:

  dim as int32 n = err( )

  print "Error #"; n

  end 1

An example using inline error handling (note: Open can also return its own error status when called as a function)

'' compile without -e switch

Dim filename As String

Do

    Line Input "Input filename: ", filename

    If filename = "" Then End

    Open filename For Input As #1

Loop Until Err() = 0

Print Using "File '&' opened successfully"; filename

Close #1

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Category: Error Handling Functions
Kind: keyword

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Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.