OPEN-FUNCTION

This function opens an existing indexed file.

If it is successful, the value in RETURN-CODE should be moved to a data item that is USAGE HANDLE. This data item is passed as the open file handle to the other file handling functions.

If it fails, RETURN-CODE is set to ZERO.

After the file is opened, the primary key is set as the current key of reference and it is positioned at the beginning of the file.

This function only opens already existing files. If the file does not exist, the function fails, even when opening for output.

Syntax

SET OPEN-FUNCTION TO TRUE    CALL "I$IO" USING IO-FUNCTION                    name                    mode                    lParms             GIVING returnCode

Parameters:

name	the name of the file to open.
mode	one of the following values (defined in isfilesys.def):
	Finput Foutput Fio Fextend	Open for input only. Open for output only. Open for input and output. Same as Foutput.
	mode may also have one of the following flags (defined in isfilesys.def) added to it to indicate file locking options:
	Fmulti_lock Fread_lock Fwrite_lock Fmass_update FEncrypt Ftrans FBulk_addition	Keep locks on multiple records. Locks file against other updaters. Locks file against all others. Same as Fwrite_lock. Consider the file as encrypted. Extends locking rules for transaction management. Same as Fwrite_lock.
lParms	The l_parms parameter is the same as the l_parms parameter passed when using the MAKE-FUNCTION opcode.   This parameter is a string that contains three comma-separated numbers.   Valid values are (in order): • the maximum record size, • the minimum record size, • the number of keys for the file,   If the maximum record size does not match the minimum record size, then variable sized records are implied.   If the parameter is initialized, the runtime retrieves the values from the file during the open. If the parameter is set, the runtime checks the values against file characteristics and returns a mismatch error if they don’t match.

Return code:

returnCode can be any signed numeric data item and provides additional information:

>0	File handle.
0	Operation failed.