SCO OpenServer
tc_tlock(D3oddi)
tc_tlock, tc_tunlock, tc_ctlock, tc_ctunlock --
lock and unlock portions of a tty structure
Syntax
#include <sys/tty.h>
int tc_tlock(struct tp)
critical code
int tc_tunlock(struct tp, ...)
int tc_ctlock(struct tp)
critical code
int tc_tunlock(struct tp, ...)
Description
The
tc_tlock( )
functions provide mutual exclusion for
critical code sections
that access a tty structure.
tc_tlock( )
sets a lock unconditionally.
tc_ctlock( )
sets a lock only if one does not currently exist;
if a lock already exists,
it returns immediately.
Arguments
tp-
Pointer to the appropriate tty structure.
Return values
tc_tlock( )
and
tc_ctlock( )
return the previous spl value.
tc_tunlock( )
does not return a value.
Usage
Context and synchronization
Non-blockable, interrupt, user, or blockable
context.
Hardware applicability
All
Version applicability
oddi:
2mp, 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp
SVR5 DDI compatibility
SVR5 TTY drivers are implemented
as STREAMS drivers
so there is no direct parallel to these functions.
See
``Spin locks (DDI)'' in HDK Technical Reference
for information about the locking facilities
that are supported for DDI drivers.
References
lockb(D3oddi)
``Notes and examples for multithreaded TTY drivers'' in Developing SCO OpenServer 5 kernel drivers.
19 June 2005
© 2005 The SCO Group, Inc. All rights reserved.
OpenServer 5 HDK - June 2005