wait_task_stopped(9) [centos man page]

WAIT_TASK_STOPPED(9)						   Driver Basics					      WAIT_TASK_STOPPED(9)

NAME

       wait_task_stopped - Wait for TASK_STOPPED or TASK_TRACED

SYNOPSIS

       int wait_task_stopped(struct wait_opts * wo, int ptrace, struct task_struct * p);

ARGUMENTS

       wo
	   wait options

       ptrace
	   is the wait for ptrace

       p
	   task to wait for

DESCRIPTION

       Handle sys_wait4 work for p in state TASK_STOPPED or TASK_TRACED.

CONTEXT

       read_lock(tasklist_lock), which is released if return value is non-zero. Also, grabs and releases p->sighand->siglock.

RETURNS

       0 if wait condition didn't exist and search for other wait conditions should continue. Non-zero return, -errno on failure and p's pid on
       success, implies that tasklist_lock is released and wait condition search should terminate.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						      WAIT_TASK_STOPPED(9)

WAIT(2) 							System Calls Manual							   WAIT(2)

NAME

       wait - wait for process to terminate

SYNOPSIS

       wait(status)
       int *status;

       wait(0)

DESCRIPTION

       Wait  causes its caller to delay until a signal is received or one of its child processes terminates.  If any child has died since the last
       wait, return is immediate; if there are no children, return is immediate with the error bit set (resp. with a value of -1  returned).   The
       normal return yields the process ID of the terminated child.  In the case of several children several wait calls are needed to learn of all
       the deaths.

       If (int)status is nonzero, the high byte of the word pointed to receives the low byte of the argument of exit when  the	child  terminated.
       The  low  byte  receives the termination status of the process.	See signal(2) for a list of termination statuses (signals); 0 status indi-
       cates normal termination.  A special status (0177) is returned for a stopped process which has not terminated and can  be  restarted.   See
       ptrace(2).  If the 0200 bit of the termination status is set, a core image of the process was produced by the system.

       If the parent process terminates without waiting on its children, the initialization process (process ID = 1) inherits the children.

SEE ALSO

       exit(2), fork(2), signal(2)

DIAGNOSTICS

       Returns -1 if there are no children not previously waited for.

ASSEMBLER

       (wait = 7.)
       sys wait
       (process ID in r0)
       (status in r1)

       The high byte of the status is the low byte of r0 in the child at termination.

																	   WAIT(2)