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with a value of zero (6 on page 3-7) must be passed. This indicates to the API
that you want exception messages sent.
Optional Parameter Group
Some of the APIs have optional parameters; the optional parameters form a group.
You must either include or exclude the entire group. You cannot use one of these
parameters by itself. You must include all preceding parameters.
The API can be called two ways: either with the optional parameters or without the
optional parameters.
The Retrieve Job Description Information API has no optional parameter groups.
The List Job (QUSLJOB) API is an example of an API with an optional parameter
group.
Format
The Format topic describes a format name, which for the Retrieve Job Description
(QWDRJOBD) API is JOBD0100. Listed within the format are the individual fields
that contain the attributes of the job description. The offset in the
Dec
(decimal
offset) column for the hold on job queue field (hold parameter on the Retrieve Job
Description command) begins at decimal offset 76. For more information on this
format, see “JOBD0100 Format” on page 3-30.
The fields in the format do not occur in any particular sequence. You have to scan
the format to determine what you want.
This API has only a single format; other APIs may have multiple formats where
each format has different levels of information. With multiple formats, a format
name parameter allows you to specify which format you want to retrieve.
Field Descriptions
The Field Descriptions topic describes the fields found in the format. The contents
of the format are presented in alphabetical sequence and not in the sequence of
the fields defined in the format. In the Retrieve Job Description Information API
example, you can find the description of the hold on job queue field. The field does
not use the parameter name found on the Create Job Description (CRTJOBD)
command.
Error Messages
The Error Messages topic lists error messages that can occur when you use the
API. These are message IDs that normally exist in the QCPFMSG file. You may
want to program for these messages regardless of the high-level language that you
are using. If you need more detail about the messages, use the Display Message
Description (DSPMSGD) command.
Extracting a Field from the Format
The format describes where the field that you want is located within the receiver
variable. An offset is shown in both decimal and hexadecimal. Depending on
which language you use, either offset may be helpful. For CL and RPG, you would
normally use the decimal offset. With any offset, it is important to remember
whether your language works with an offset from a base of 0 or a base of 1. The
format tables in the
System API Reference
are prepared for languages that work
Chapter 3. Common Information across APIs—Basic (OPM) Example 3-5