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.Dd November 30, 2015
.Dt _KSEM 2
.Os
.Sh NAME
.Nm _ksem ,
.Nm _ksem_init ,
.Nm _ksem_open ,
.Nm _ksem_close ,
.Nm _ksem_unlink ,
.Nm _ksem_destroy ,
.Nm _ksem_getvalue ,
.Nm _ksem_post ,
.Nm _ksem_wait ,
.Nm _ksem_timedwait ,
.Nm _ksem_trywait
.Nd back-end implementation for POSIX semaphores
.Sh SYNOPSIS
.In sys/ksem.h
.Ft int
.Fn _ksem_init "int value" "intptr_t *idp"
.Ft int
.Fn _ksem_open "const char *name" "int oflag" "mode_t mode" "unsigned int value" "intptr_t *idp"
.Ft int
.Fn _ksem_close "intptr_t id"
.Ft int
.Fn _ksem_unlink "const char *name"
.Ft int
.Fn _ksem_destroy "intptr_t id"
.Ft int
.Fn _ksem_getvalue "intptr_t id" "unsigned int *value"
.Ft int
.Fn _ksem_post "intptr_t id"
.Ft int
.Fn _ksem_wait "intptr_t id"
.Ft int
.Fn _ksem_timedwait "intptr_t id" "const struct timespec *abstime"
.Ft int
.Fn _ksem_trywait "intptr_t id"
.Sh DESCRIPTION
The
.Fn _ksem_*
family of system calls provide the kernel implementation of POSIX
semaphores.
.Sh RETURN VALUES
Successful calls to the
.Fn _ksem_*
system calls return a value of zero.
Otherwise, \-1 is returned and
.Va errno
is set to provide more information.
.Sh ERRORS
Please see the section 3 manual pages for specific error information.
.Sh SEE ALSO
.Xr sem_close 3 ,
.Xr sem_destroy 3 ,
.Xr sem_getvalue 3 ,
.Xr sem_init 3 ,
.Xr sem_open 3 ,
.Xr sem_post 3 ,
.Xr sem_unlink 3 ,
.Xr sem_wait 3 ,
.Xr sem 4
.Sh HISTORY
Most of the
.Fn _ksem_*
system calls first appeared in
.Nx 2.0 .
The
.Fn _ksem_timedwait
system call first appeared in
.Nx 5.0 .