DosMonOpen

This call gains access to a character device data stream.

Syntax

DosMonOpen (Devname, Handle)

Parameters

Devname (PSZ) - input

Address of the device name string.

Handle (PHMONITOR) - output

Address of the handle for the monitor. This value must be passed to DosMonReg to communicate with the device, and is passed to DosMonClose to close the connection to the monitor.

Return Code

rc (USHORT) - return

Return code descriptions are:

• 0 - NO_ERROR
• 110 - ERROR_OPEN_FAILED
• 379 - ERROR_MON_INVALID_PARMS
• 380 - ERROR_MON_INVALID_DEVNAME

Remarks

For a detailed description of this call see the chapter "Character Device Monitors" in the IBM Operating System/2 Version 1.2 I/O Subsystems And Device Support Volume 1.

Only one DosMonOpen call is necessary per device per process. That is, several DosMonReg calls can be made using the same monitor handle to the same device. This allows monitors to be registered using different values for Index from the same process and going to the same device. When the DosMonClose is issued, all of the monitors registered on the handle is closed.

Example Code

C Binding

#define INCL_DOSMONITORS

USHORT  rc = DosMonOpen(Devname, Handle);

PSZ              Devname;       /* Device name string */
PHMONITOR        Handle;        /* Monitor handle (returned) *

USHORT           rc;            /* return code */

MASM Binding

EXTRN  DosMonOpen:FAR
INCL_DOSMONITORS    EQU 1

PUSH@  ASCIIZ  Devname       ;Device name string
PUSH@  WORD    Handle        ;Monitor handle (returned)
CALL   DosMonOpen

Returns WORD