osf1 man page for pid_unblock

pid_block(2)							System Calls Manual						      pid_block(2)

NAME
       pid_block, pid_unblock - stops (blocks) or resumes (unblocks) the specified process

SYNOPSIS
       #include <types.h> #include <sys/time.h>

       int pid_block(
	       struct timeval *tp,
	       long flags ); int pid_unblock(
	       pid_t pid,
	       long flags );

LIBRARY
       Standard C Library (libc)

PARAMETERS
       Specifies  the  timeout	value  for  the  blocked  process.   If  tp is NULL, the process sleeps until either it receives a signal or it is
       unblocked by a pid_unblock.  Specifies the process ID of the process to unblock.  Specifies flags that can be passed to the pid_block() and
       pid_unblock() functions.

									      Note

	      Currently, the only valid value for flags is NULL.

DESCRIPTION
       The  pid_block()  function  blocks  execution  of the process until one of the following conditions occurs: The process is unblocked by the
       pid_unblock() function.	A signal is sent to the process.  The optional timeout period expires.

       The pid_unblock function forces the specified process, previously suspended via a call to pid_block, to be made runnable.

       Unless you are operating with superuser authority, pid_unblock can affect only processes that  you  own.   When	operating  with  superuser
       authority, you can unblock any process.

NOTES
       The  pid_block  and pid_unblock functions are not portable. The behavior of these functions when called from a multithreaded application is
       nondeterministic.

RETURN VALUES
       Upon successful completion, the pid_block() and pid_unblock() functions return a value of 0.  Otherwise, they return a value of -1 and  set
       errno  to  indicate  the error: The pid parameter specified an invalid address.	The tp parameter specified a time that was too large to be
       handled, or the pid specified to the pid_unblock function was not found.  The real or saved user ID does not match the  real  or  effective
       user  ID  of  the  target  process or the calling process does not have appropriate privilege.  A signal interrupted the suspended process.
       System call timed out.

FILES
																      pid_block(2)