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Programmatic Access to DIRECTORY output?

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The Question is:

How do I capture the output of a system command and save it in a file to be
 accessed from an application.  For example, how would I save the dir listing
 in a file to be opened in a program that would use that information?

The Answer is :

  Most OpenVMS command operations have an API equivalent.
  In this case, please use the lib$find_file and related RTL calls or
  use the C opendir, readdir, and related calls directly within the
  application to implement the necessary directory scan, please do not
  attempt to capture and parse the command output of DCL commands.
  (The format of the command output can potentially change, leading
  to problems with programs that attempt to parse the output.)
  The C system call does not offer output redirection, but the
  lib$spawn call -- the call used to implement the C system call
  on OpenVMS -- does.  Alternatively, various DCL-level output
  redirection operations are possible, with the DCL command PIPE
  as a salient example of one approach.

answer written or last revised on ( 31-MAY-2001 )

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