I$Dup

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Duplicate Path Returns a synonymous path number
OS9 I$Dup 103F 82

Entry Conditions

A old path number (number of path to duplicate)

Exit Conditions

A new path number (if no error)

Error Output

CC carry set on error

B error code, if any

Additional Information

  • The Duplicate Path returns another, synonymous path number for the file or device specified by the old path number.
  • The shell uses the Duplicate Path call when it redirects I/O.
  • System calls can use either path number (old or new) to operate on the same file or device.
  • Makes sure that no more than one process is performing I/O on any one path at the same time. Concurrent I/O on the same path can cause unpredictable results with RBF files.
  • The I$Dup call always uses the lowest available path number. This lets you manipulate standard I/O paths to contain any desired paths.