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4D v14

SVG_Read_last_error


SVG_Read_last_error -> Function result

Parameter	Type	Description
Function result	Longint	Number of last error

Description

The SVG_Read_last_error command returns the number of the last error that occurred during the execution of a 4D SVG component command and resets this error.

The error number returned can be specific to a component command or may be an error generated by 4D. The following errors are generated by the component:

8850	Insufficient number of parameters
8851	Invalid parameter type
8852	Invalid reference
8853	Incorrect value for attribute
8854	The element does not accept this command
8855	Invalid (ID not found in document) object name (symbol, marker, filter, etc.)
8856	DTD file not found
8857	Incorrect value for a parameter
8858	Unknown error

Example 1

Given the "SVG_error_mgmt" method of the example for the SVG_Set_error_handler command:

  `Installation of error-handling method

 $ Error_Method_Txt:=SVG_Set_error_handler("SVG_error_mgmt")

  `from now on it is the SVG_error_mgmt method that will be executed in the case of an error

 

  `Creation of new SVG document

 $SVG:=SVG_New(1200;900;"SVG Component Test";"";True)

 SVG_SET_VIEWBOX($SVG;0;0;1500;1000)

 

 If(SVG_Read_last_error=0)

 

    ...

 

 Else

  `The SVG_error_mgmt method has been called and has received the error number

 End if

 

  `Uninstalling of error-handling method

 SVG_Set_error_handler

Example 2

Given the following SVG_error_mgmt method:

 C_LONGINT($1)

 C_TEXT($2)

 

  `Keep the error and the context

 errorNumber:=$1

 commandName:=$2

 

  `Set the OK system variable to 0

 OK:=0

This method can be used as follows:

  ` Installation of error-handling method

 $ Error_Method_Txt:=SVG_Set_error_handler("SVG_error_mgmt")

 

  ` Creation of new SVG document

 $SVG:=SVG_New(1200;900;" SVG Component Test ";"";True)

 SVG_SET_VIEWBOX($SVG;0;0;1500;1000)

 If(OK=1)

 

    ...

 

 Else

    ALERT("Error No."+String(errorNumber)+" during execution of the command \""+commandName+"\"")

 End if

 

  ` Uninstalling of error-handling method

 SVG_Set_error_handler