Opening and Closing Files

The OPEN command in PRO/5 is used to associate a PRO/5 channel with a file or device.

Opening Files

The OPEN command in PRO/5 is used to associate a PRO/5 channel with a file or device. After opening a file PRO/5 positions the file pointer to the first record or byte in the file.

Syntax

OPEN (chan)"file"

Parameter	Description
chan	A channel that is not currently in use. (The UNT variable returns an unused channel.)
"file"	Name and path of the file to be opened.

Opening any PRO/5 file with the ISZ= option causes it to be opened as a STRING file. (For PROGRAM files, use ISZ=-1.) This causes PRO/5 to treat the file as though it could not find a PRO/5 header of the file (a STRING file). This allows you to directly modify structure of the file. The file itself is locked for the duration of the ISZ= open and may not be OPENed on more than one channel.

Closing Files

A channel may be closed by using the CLOSE command. In addition, the BEGIN, START, END, and STOP verbs will close all OPENed channels except channel 0.

Note:

In PRO/5 15.01 and higher, and BBj 15.10 and higher, the OPEN verb by default is restricted from opening pipes (commands starting with "<", ">", or "|") in console mode. This is to protect against accidentally overwriting a data file as a side effect of inadvertently specifying a pipe expression. To open a pipe at the console, set SETOPTS byte 9 bit $10$ or include MODE="PIPE" in the OPEN.