ibm-information-center/dist/eclipse/plugins/i5OS.ic.rbam6_5.4.0.1/accessfile.htm

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<h1 class="topictitle1">Access files</h1>
<div><p>A file must exist when compiling a CL module or OPM program that
uses it.</p>
<div class="section"> <p>The compiler accesses files when compiling a program module that
has a <span class="cmdname">Declare File (DCLF)</span> command. The file does not have
to exist when creating a program or service program that uses the module.</p>
<p>Enter
Data Description Specifications (DDS) into a source file before creating it.
The DDS describes the record formats and the fields within the records. Additionally,
the system compiles this information to create the file object through the <span class="cmdname">Create
Display File (CRTDSPF)</span> command. </p>
<div class="note"><span class="notetitle">Note:</span> You can create other
types of files from DDS, and each type has its own command: <span class="cmdname">Create
Physical File (CRTPF)</span> and <span class="cmdname">Create Logical File (CRTLF)</span> are
two that create files that you can use in CL programs and procedures.</div>
<p>The
fields that are described in the DDS can be input or output fields (or both).
The system declares the fields in the CL program or procedure as variables
when it compiles a program or module. The program manipulates data from display
through these variables.</p>
<p>If you do not use DDS to create a physical
file, the system declares a CL variable to contain the entire record. This
variable has the same name as the file, and its length is the same as the
record length of the file.</p>
<p>CL programs and procedures cannot manipulate
data in any types of files other than display files and database files, except
with specific CL commands.</p>
<p>Deletion of the DDS after creating the file
is possible but not recommended. You can delete the file after the system
compiles the CL program or module that refers to the file. This is true provided
the file exists when the command referring to it, such as a <span class="cmdname">Receive
File (RCVF)</span>, is processed in the program.</p>
<p>The rules on qualified
names that are described here for command definitions also apply to files.</p>
</div>
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<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="except.htm" title="To access command definitions or files from a CL program, the command definitions or files must exist at creation time of the program and must exist when the command that refers to them runs.">Access command definitions, files, and procedures</a></div>
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<div class="reltasks"><strong>Related tasks</strong><br />
<div><a href="wfile.htm" title="Two types of files are supported in CL procedures and programs: display files and database files.">Work with files in CL procedures</a></div>
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