Decodes the device handler's special file name appended to the open call.
#include <sys/device.h>
int dlcmpx (devno, chanp, channame)
dev_t devno;
int *chanp;
char *channame;
Note: The dlc prefix is replaced with the three-digit prefix for the specific GDLC device manager being opened.
The operating system calls the dlcmpx entry point when a generic data link control (GDLC) channel is allocated. This routine decodes the name of the device handler appended to the end of the GDLC special file name at open time. GDLC allocates the channel and returns the value in the chanp parameter.
This routine is also called following a close subroutine to deallocate the channel. In this case the chanp parameter is passed to GDLC to identify the channel being deallocated. Since GDLC allocates a new channel for each open subroutine, a dlcmpx routine follows each call to the dlcclose routine.
The following return values are defined in the /usr/include/sys/errno.h file:
0 | Indicates a successful operation. |
EBADF | Indicates a bad file number. |
EINVAL | Indicates an invalid value. |
Each GDLC supports the dlcmpx entry point as its switch table entry for the open and close subroutines. The file system calls this entry point from the process environment only.
The close subroutine, open subroutine.
The ddmpx device entry point.
The dlcclose entry point for the GDLC device manager, dlcopen entry point for the GDLC device manager.
Generic Data Link Control (GDLC) Environment Overview in AIX Version 4.3 Communications Programming Concepts.