Reference Guide

ZCOM C I/F Library Routines
PTFIND (3X)
Chapter 4164
Method 3: Retrieve the next terminal whose table has a sequence of
matching bit patterns.
This mode is similar to Method 2 except that the caller also specifies a
mask buffer, which is used to mask some unused bits in the physical
terminal table before comparing with the specified data.
The mask buffer is AND’ed with the table content before comparison.
Hence, the mask buffer should contain zeros for those unused bits and
ones for those bits to be compared. The data buffer should have zeros for
those unused bits, 0 or 1 for the bits to be compared.
Similarly, the search starts from the next terminal after the specified
ZLU. (In fact, method 2 may be treated as a special case of this, if the
mask buffer contains all ones.)
The libraries libzcom_c.a and libpthread.a must be linked into the calling
program by giving the options “-lzcom_c -lpthread” to cc(1) or ld(1).
Threads
Considerations
This routine may be called from a multi-threaded application using the
POSIX (1003.1c) kernel threads API package. This routine has the
following characteristics when called by a multi-threaded application:
cancellation point Thread cancellation can occur when a thread
calls this routine.
async-cancel unsafe The calling thread’s cancelability type must be
PTHREAD_CANCEL_DEFERRED if
cancellation is enabled.
async-signal unsafe It cannot be called from a signal handler.
fork unsafe It cannot be called by a child process after
fork(2) but before exec(2).