Open file

Purpose: Open file for reading and writing.

open-file <file name> file-id <file id> \
    [ new-truncate ] \
    [ status <status> ]

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Opens file given by <file name> for reading and writing and creates an open file variable identified by <file id>.

<file name> can be a full path name, or a path relative to the application home directory (see directories).

You can obtain the status of file opening via <status> number (in "status" clause). The <status> is GG_OKAY if file is opened, or GG_ERR_OPEN if could not open file.

If "new-truncate" clause is used, a new file is created if it doesn't exist, or it is truncated if it does.

Examples

Create a file (or truncate an existing one), write 25,000 rows and the read back those rows and display them, then close file:

%% /ofile public
    // Create new file, or truncate an old file if it exists
    open-file "testwrite" file-id nf new-truncate

    // Write 25000 rows
    start-loop repeat 25000 use i
       (( line
       @some text in line <<print-out i>>
       )) notrim
       string-length line to line_len
       write-file file-id nf from line length line_len
    end-loop

    // Rewind back to the beginning
    file-position set 0 file-id nf

    // Read all 25000 rows back, and print them out
    read-file file-id nf  to whole_file
    print-out whole_file

    // Close the file
    close-file file-id nf
%%

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