Using the vars Tag

Use the <vars> tag to extract values of a specified type, size, and offset from a call parameter. You can then refer to the extracted values in the <rep> and <hc> tags using the %var_name notation.

The <arg> subtag characterizes the argument of interest. Attributes are:

var: Specifies the variable name.
param: Specifies the index of the parameter.
type: Specifies the variable type.
offset: Specifies the offset of the field in bytes.
bitoffset: Specifies the offset of the field in bits.
size: Specifies the size of the field in bytes.
bitsize: Specifies the size of the field in bits.

Additional attributes for PL/I are:

len: Specifies the size of a character or bit string field.
mode: Specifies the binary or decimal mode for a numeric field.
scale: Specifies the scale of a fixed-point numeric field.
prec: Specifies the precision of a fixed-point or floating-point numeric field.
varying: Specifies whether a bit string variable is encoded as a varying-length string in the structure (yes or no, the default).

Supported data types are described in the language-specific sections below.

Example

Suppose a call to a database-entry API looks like this:

CALL 'DBNTRY' USING DB-USER-ID
                    DB-XYZ-REQUEST-AREA
                    XYZ01-RECORD
                    DB-XYZ-ELEMENT-LIST.

If the second parameter contains a 3-character table name in bytes 6-8, then the following definition extracts the name for use as the right end of a relationship:

<vars>
  <arg var='TableName'
       param='2'
       type='auto'
       offset='5'
       size='3'/>
</vars>
<rep>
  <rel>
    <target type='TABLE'
            name='%TableName'/>
    .
    .
    .
  </rel>
</rep>