PRB: SYS(2018) May Return More Than the Message Parameter (190624)


The information in this article applies to:

  • Microsoft Visual FoxPro for Windows 5.0
  • Microsoft Visual FoxPro for Windows 5.0a
  • Microsoft Visual FoxPro for Windows 6.0
This article was previously published under Q190624

SYMPTOMS

When a table is created programmatically, the Check clause can be used to perform field level validations. When a field level error occurs, either the SYS(2018) or the AERRORS function can be used to display the source of the error. In Visual FoxPro 3.0, the error message parameter that was involved in the generated error was returned. This behavior is different in Visual FoxPro 5.0 and 6.0. In the latter versions of Visual FoxPro, the entire error message is returned by default.

RESOLUTION

To work around this behavior use the Error cause in the CREATE TABLE, Check statement, as shown in the MORE INFORMATION section.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Run the following code to see the behavior. When the code executes, the program continues when an error occurs and the error is displayed using SYS(2018) and the AERRORs array. Run the code and first do not select the work around and you will see the default error message parameter. If you want to see the work around, the CREATE TABLE with the ERROR clause is used.

    Sample Code

          *-- Code begins here.
      CLEAR
      ON ERROR *
      IF ADIR(myTestFiles, "sys2018*.dbc") > 0
          nErase=MESSAGEBOX("Erase SYS(2018) Files?",4)
      ENDIF
      IF nErase = 6
          CLOSE DATA
          ERASE sys2018.*
          CREATE DATA sys2018
          OPEN DATA sys2018
          nError = MESSAGEBOX("Workaround?",4)
          IF nError = 6
              CREATE TABLE sys2018 (NAME c(10) CHECK NAME="Moe" ;
              ERROR "NAME")
          ELSE
              CREATE TABLE sys2018 (NAME c(10) CHECK NAME="Moe")
          ENDIF
      ENDIF

      INSERT INTO sys2018 VALUES ("NotMoe")

      &&This causes a validation error.
      ?"SYS(2018) = " + SYS(2018)
      ?
      ?
      =AERROR(aTest)
      DISPLAY MEMO LIKE aTest
      CLOSE DATA ALL
      ON ERROR
   *-- Code ends here.
After the preceding program is finished, the files created can be deleted by issuing the following command: 
   ERASE SYS2018.*

REFERENCES

Visual FoxPro Help; search on: SYS(2018); AERROR
Modification Type:MajorLast Reviewed:12/11/1999
Keywords:kbprb KB190624
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