xref: /netbsd-src/lib/libpthread/pthread.3 (revision 661e3b515951b1cf67bf9e9a9d06b3f8932a6b39)

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.Dd November 22, 2016
.Dt PTHREAD 3
.Os
.Sh NAME
.Nm pthread
.Nd POSIX Threads Library
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Pp
.Nm cc
.Op Ar flags
.Ar files
.Fl lpthread
.Op Ar libraries
.Sh DESCRIPTION
The
.Nm
library provides an implementation of the standard POSIX threads
library.
.Pp
The
.Nx
implementation is based on 1:1 thread model, therefore each
.Nm
has a kernel thread, called a light-weight process (LWP).
.Pp
Note that the system private thread interfaces upon which the
.Nm
library is built are subject to change without notice.
In order to remain compatible with future
.Nx
releases, programs must be linked against the dynamic version of the
thread library.
Statically linked programs using the POSIX
threads framework may not work when run on a future version of the system.
.Sh FUNCTIONS
The following functions comprise the core of the
.Nm
library:
.Bl -column -offset indent "pthread_barrier_destroy(3)" "XXX"
.It Sy Function Ta Sy Description
.It Xr pthread_attr 3 Ta thread attribute operations
.It Xr pthread_barrier_destroy 3 Ta destroy a barrier
.It Xr pthread_barrier_init 3 Ta create a barrier
.It Xr pthread_barrier_wait 3 Ta wait for a barrier
.It Xr pthread_barrierattr 3 Ta barrier attribute operations
.It Xr pthread_cancel 3 Ta cancel the execution of a thread
.It Xr pthread_cleanup_push 3 Ta add or remove cleanup functions
.It Xr pthread_cond_broadcast 3 Ta unblock one or more threads
.It Xr pthread_cond_destroy 3 Ta destroy a condition variable
.It Xr pthread_cond_init 3 Ta create a condition variable
.It Xr pthread_cond_wait 3 Ta wait for a condition variable
.It Xr pthread_condattr 3 Ta condition attribute operations
.It Xr pthread_create 3 Ta create a new thread
.It Xr pthread_detach 3 Ta detach a thread
.It Xr pthread_equal 3 Ta compare thread identifiers
.It Xr pthread_exit 3 Ta terminate the calling thread
.It Xr pthread_getspecific 3 Ta get a thread-specific data value
.It Xr pthread_join 3 Ta wait for thread termination
.It Xr pthread_key_create 3 Ta thread-specific data key creation
.It Xr pthread_key_delete 3 Ta delete a thread-specific data key
.It Xr pthread_kill 3 Ta send a signal to a specific thread
.It Xr pthread_mutex_destroy 3 Ta free a mutex
.It Xr pthread_mutex_init 3 Ta create a mutex
.It Xr pthread_mutex_lock 3 Ta acquire a lock on a mutex
.It Xr pthread_mutex_unlock 3 Ta unlock a mutex
.It Xr pthread_mutexattr 3 Ta mutex attribute operations
.It Xr pthread_once 3 Ta dynamic package initialization
.It Xr pthread_rwlock_destroy 3 Ta destroy a read/write lock
.It Xr pthread_rwlock_init 3 Ta initialize a read/write lock
.It Xr pthread_rwlock_rdlock 3 Ta acquire a read/write lock for reading
.It Xr pthread_rwlock_unlock 3 Ta release a read/write lock
.It Xr pthread_rwlock_wrlock 3 Ta acquire a read/write lock for writing
.It Xr pthread_rwlockattr 3 Ta read/write lock attribute operations
.It Xr pthread_schedparam 3 Ta thread scheduling manipulation
.It Xr pthread_self 3 Ta get the ID of the calling thread
.It Xr pthread_setspecific 3 Ta get a thread-specific data value
.It Xr pthread_sigmask 3 Ta manipulate a thread's signal mask
.It Xr pthread_spin_destroy 3 Ta destroy a spin lock
.It Xr pthread_spin_init 3 Ta initialize a spin lock
.It Xr pthread_spin_lock 3 Ta acquire a spin lock
.It Xr pthread_spin_unlock 3 Ta release a spin lock
.It Xr pthread_testcancel 3 Ta set cancelability state
.El
.Sh ENVIRONMENT
The following environment variables affect the behavior of the library:
.Bl -tag -width "XXX"
.It Ev PTHREAD_DIAGASSERT
Possible values are any combinations of:
.Pp
.Bl -tag -width "X " -offset 1n -compact
.It Em A
Report errors to application by error return, but do not abort.
.It Em a
Abort on errors, creating a core dump for further debugging.
.It Em E
Do not log errors to stdout.
.It Em e
Log errors to stdout.
.It Em L
Do not log errors via
.Xr syslogd 8 .
.It Em l
Log errors via
.Xr syslogd 8 .
.El
.Pp
If not set in the environment, the
.Nm
library behaves as if
.Em AEL
has been specified.
.It Ev PTHREAD_STACKSIZE
Integer value giving the stack size in kilobytes.
This allows to set a smaller stack size than the default stack size.
The default stack size is the current limit on the stack size as
set with the shell's command to change limits
.Ic ( limit
for
.Xr csh 1 ,
or
.Ic ulimit
for
.Xr sh 1 ) .
.El
.Sh SEE ALSO
.Rs
.%A David R. Butenhof
.%T Programming with POSIX(R) Threads
.%D 1997
.%I Addison-Wesley
.Re
.Sh STANDARDS
The
.Nm
library conforms to
.St -p1003.1-2001 .
.Sh CAVEATS
Due to limitations in the current pthread implementation,
.Xr makecontext 3
and
.Xr sigaltstack 2
should not be used in programs which link against the
.Nm
library (whether threads are used or not).