fpt Reference: VXRMS Use of PACK BUFFER Subroutines

fpt and WinFPT Reference Manual - Command-line Commands

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VXRMS TO USE PACK BUFFER SUBROUTINES

Syntax:

VX/RMS [NOT] [TO] [USE] PACK BUFFER [SUBROUTINES] VX/RMS [NOT] [TO] [USE] VXRMS_PACK_BUFFER [SUBROUTINES] VXRMS [NOT] [TO] [USE] PACK BUFFER [SUBROUTINES] VXRMS [NOT] [TO] [USE] VXRMS_PACK_BUFFER [SUBROUTINES]

Function:

This command modifies the code generated by the commands CHANGE ISAM FILE ACCESSES TO SUB-PROGRAM CALLS, CHANGE ALL I/O TO SUB-PROGRAM CALLS and CHANGE FILE I/O TO SUB-PROGRAM CALLS. When unformatted READ and WRITE statements are converted to sub-program calls, fpt transfers the data to be read or written to or from a memory buffer. If PACK BUFFER subroutines are specified, all items in a record are transferred by a single call to a subroutine with multiple arguments. The subroutines are named VXRMS_PACK BUFFER and VXRMS_UNPACK_BUFFER. If PACK BUFFER subroutines are not specified, each datum is transferred by a separate call to VXRMS_TO_BUFFER or VXRMS_FROM_BUFFER.

The VXRMS_TO_BUFFER and VXRMS_FROM_BUFFER routines are always used if the original I/O statement contains implied DO loops.

Where to Use this Command

Operating system command line	Yes
Configuration file, config.fsp	Yes
Specification (fsp) files, *.fsp	Yes
Interactively, to FPT> prompt	Yes
Interactive command files	Yes
Embedded in the Fortran code	Yes

Default

The VXRMS_PACK_BUFFER routines are used by default.

Examples

The statement:

READ (1) I,J

is rewritten in response to the commands:

% vx/rms to use pack buffer % change i/o to sub-program calls

to:

! fpt READ (1)I,J CALL VXRMS_READ('UNIT=',1,%VAL(0)) CALL VXRMS_UNPACK_BUFFER(%REF(I),4,%REF(J),4,%VAL(0))

If the user specifies:

% vx/rms not to use pack buffer

the code generated is:

! fpt READ (1)I,J CALL VXRMS_READ('UNIT=',1,%VAL(0)) CALL VXRMS_INIT_BUFFER CALL VXRMS_FROM_BUFFER(%REF(I),4) CALL VXRMS_FROM_BUFFER(%REF(J),4)