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

tpSpecifies 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. 

pidSpecifies the process ID of the process to unblock. 

flagsSpecifies 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:

[EFAULT]
The pid parameter specified an invalid address. 

[EINVAL]
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. 

[EPERM]
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.

[EINTR]
A signal interrupted the suspended process.

[ETIME]
System call timed out.

FILES

/usr/include/sys/time.h

/usr/include/types.h