Status variable handling

I4GL and Genero BDL support the status variable differently.

Status untouched on successful LET

When using WHENEVER ANY ERROR, IBM® Informix® 4GL resets the status variable to zero after a successful LET instruction, while Genero BDL leaves it untouched.

With Genero BDL, the status variable setting is slightly different to I4GL: While SQL or screen interaction statements set or reset status variable. When using WHENEVER ANY ERROR, expressions will set the status on error, but will not reset status to zero on success: The status variable keeps the last value until a new expression error in thrown.

For example:

MAIN
    DEFINE x, s1, s2 INTEGER
    WHENEVER ANY ERROR CONTINUE
    LET x = "abc"  LET s1 = status
    LET x = 123    LET s2 = status
    DISPLAY "s1 = ", s1
    DISPLAY "s2 = ", s2
END MAIN

Output with I4GL:

s1 =       -1213
s2 =           0

Output with Genero BDL:

s1 =       -1213
s2 =       -1213

If the program needs to check the status variable for expressions with WHENEVER ANY ERROR CONTINUE, the status variable must be manually reset to zero before the execution the expression.

Status always set on invalid MDY parameters

With IBM Informix 4GL, if the MDY() function gets invalid month, day or year, the status variable is set to an error number, only in the context of WHENEVER ANY ERROR. In the context of WHENEVER ERROR, status is untouched.

Genero BDL will always set the status variable when using the MDY() function: If the parameters are valid, status is reset to zero. If parameters are invalid, status is set to the corresponding error number.

For example:

MAIN
    DEFINE d DATE
    LET status = -1
    LET d = MDY(1,1,2000)
    DISPLAY status
    LET d = MDY(99,1,2000)
    DISPLAY status
    WHENEVER ANY ERROR CONTINUE
    LET d = MDY(99,1,2000)
    DISPLAY status
END MAIN

Output with I4GL:

         -1
          0
      -1205

Output with Genero BDL:

          0
      -1205
      -1205