Parameter list for conversion procedures

At invocation, registers are set, and the conversion procedure uses the standard exit parameter list (EXPL).

Begin program-specific programming interface information.A conversion procedure does not use an exit-specific parameter list. Instead, the area pointed to by register 1 at invocation includes three words, which contain the addresses of the following items:

  1. The EXPL parameter list
  2. A string value descriptor that contains the character string to be converted
  3. A copy of a row from SYSIBM.SYSSTRINGS that names the conversion procedure identified in TRANSPROC.

The length of the work area pointed to by the exit parameter list is generally 512 bytes. However, if the string to be converted is ASCII MIXED data (the value of TRANSTYPE in the row from SYSSTRINGS is PM or PS), then the length of the work area is 256 bytes, plus the length attribute of the string.

The string value descriptor: The descriptor has the following formats:

Table 1. Format of string value descriptor for a conversion procedure
Name Hex offset Data type Description
FPVDTYPE 0 Signed 2-byte integer Data type of the value:
Code
Means
20
VARCHAR
28
VARGRAPHIC
FPVDVLEN 2 Signed 2-byte integer The maximum length of the string
FPVDVALE 4 None The string. The first halfword is the string's actual length in characters. If the string is ASCII MIXED data, it is padded out to the maximum length by undefined bytes.

The row from SYSSTRINGS: The row copied from the catalog table SYSIBM.SYSSTRINGS is in the standard Db2 row format. The fields ERRORBYTE and SUBBYTE each include a null indicator. The field TRANSTAB is of varying length and begins with a 2-byte length field.End program-specific programming interface information.