Open (Dataset function): Difference between revisions
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===Syntax terms=== | ===Syntax terms=== | ||
<table class="syntaxTable"> | <table class="syntaxTable"> | ||
<tr><th>% | <tr><th>%rc</th> | ||
<td>A variable to receive the return code from the <var> | <td>A variable to receive the return code from the <var>Open</var> method, indicating whether or not the open succeeded. | ||
whether or not the open succeeded. | |||
Possible return codes are: | Possible return codes are: | ||
<dl> | <dl> | ||
| Line 22: | Line 21: | ||
<dt>15 | <dt>15 | ||
<dd>Parallel stream has incompatible parallel members. | <dd>Parallel stream has incompatible parallel members. | ||
</dl> | </dl> | ||
</td></tr> | </td></tr> | ||
<tr><th> | <tr><th>dataset</th> | ||
<td>A variable containing a reference to a <var>Dataset</var> object for which the | <td>A variable containing a reference to a <var>Dataset</var> object for which the underlying dataset is to be opened. | ||
underlying dataset is to be opened. | |||
</td></tr></table> | </td></tr></table> | ||
==Usage notes== | ==Usage notes== | ||
<ul> | <ul> | ||
| Line 37: | Line 34: | ||
from the DSCB (or CMS or VSE equivalents) will tend to override attributes | from the DSCB (or CMS or VSE equivalents) will tend to override attributes | ||
set explicitly before the open. | set explicitly before the open. | ||
<li>An | <li>An <var>Open</var> of a dataset or stream usually places an exclusive lock on the | ||
dataset or stream until it is closed. | dataset or stream until it is closed. | ||
This means no other thread can access the dataset while it is opened. | This means no other thread can access the dataset while it is opened. | ||
Revision as of 22:04, 20 May 2011
Open this dataset (Dataset class)
This function opens the dataset associated with a Dataset object.
Syntax
[%rc =] dataset:Open
Syntax terms
| %rc | A variable to receive the return code from the Open method, indicating whether or not the open succeeded.
Possible return codes are:
|
|---|---|
| dataset | A variable containing a reference to a Dataset object for which the underlying dataset is to be opened. |
Usage notes
- An Open can modify the BlockSize, RecordLength, RecordFormat, or NumberOfBuffers properties. This is especially likely for input datasets where the dataset attributes from the DSCB (or CMS or VSE equivalents) will tend to override attributes set explicitly before the open.
- An Open of a dataset or stream usually places an exclusive lock on the dataset or stream until it is closed. This means no other thread can access the dataset while it is opened.