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pthread_rwlockattr_getpshared()
Get the process-shared attribute of a read-write lock attribute object

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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
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  The System Architecture guide accompanies the QNX OS and is intended for both application developers and end-users.
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  - C Library Reference
    - What's in a Function Description?
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      - pathconf()
        Return the value of a configurable limit
      - pathfind(), pathfind_r()
        Search for a file in a list of directories
      - pathmgr_link()
        Create a node in the path space that represents the mountpoint of a device or filesystem
      - pathmgr_symlink()
        Create a symlink
      - pathmgr_unlink()
        Remove a link
      - pause()
        Suspend the calling thread until it runs a signal handler
      - _PAYLOAD_OF()
        Generate a pointer to the payload that follows the specified header member of an object
      - pci_*()
        Connect to the PCI server
      - pclose()
        Close a pipe
      - perror()
        Print an error message associated with errno
      - pipe()
        Create a pipe
      - pipe2()
        Create a pipe with additional control flags.
      - poll()
        Multiplex input/output over a set of file descriptors
      - popen()
        Execute a command, creating a pipe to it
      - posix_devctl()
        Control a device
      - posix_fadvise(), posix_fadvise64()
        Provide advisory information about the expected use of a file
      - posix_fallocate(), posix_fallocate64()
        Allocate space for a file on the filesystem
      - posix_madvise()
        Provide advisory information about the expected use of memory
      - posix_mem_offset(), posix_mem_offset64()
        Get the physical address and length of a mapped memory block
      - posix_memalign()
        Allocate aligned memory
      - posix_openpt()
        Open a pseudo-terminal device
      - posix_spawn(), posix_spawnp()
        Spawn a process
      - posix_spawn_file_actions_addclose()
        Add a close a file descriptor action to a spawn file actions object
      - posix_spawn_file_actions_adddup2()
        Add a duplicate a file descriptor action to a spawn file actions object
      - posix_spawn_file_actions_addopen()
        Add an open a file action to a spawn file action object
      - posix_spawn_file_actions_destroy()
        Destroy a spawn file actions object
      - posix_spawn_file_actions_init()
        Initialize a spawn file actions object
      - posix_spawnattr_destroy()
        Destroy a spawn attributes object
      - posix_spawnattr_getaslr()
        Return the address space layout randomization (ASLR) setting from a posix_spawn() attribute structure
      - posix_spawnattr_getcred()
        Get the user and group ID attributes from a spawn attributes object
      - posix_spawnattr_getflags()
        Get the POSIX flags from a spawn attributes object
      - posix_spawnattr_getpgroup()
        Get the process group attribute of a spawn attributes object
      - posix_spawnattr_getrunmask()
        Get the runmask attribute from a spawn attributes object
      - posix_spawnattr_getschedparam()
        Get the scheduling parameters attribute of a spawn attributes object
      - posix_spawnattr_getschedpolicy()
        Get the scheduling policy attribute of a spawn attributes object
      - posix_spawnattr_getsigdefault()
        Get the default signals attribute of a spawn attributes object
      - posix_spawnattr_getsigignore()
        Get the ignored signals attribute from a spawn attributes object
      - posix_spawnattr_getsigmask()
        Get the signal mask attribute of a spawn attributes object
      - posix_spawnattr_getstackmax()
        Get the maximum stack size attribute from a spawn attributes object
      - posix_spawnattr_gettypeid()
        Get the type identifier of a spawn attributes object
      - posix_spawnattr_getxflags()
        Get the POSIX flags and the QNX OS extended flags from a spawn attributes object
      - posix_spawnattr_init()
        Initialize a spawn attributes object
      - posix_spawnattr_setasid()
        Set the address space ID attribute in a spawn attributes object
      - posix_spawnattr_setaslr()
        Control how the address space layout randomization (ASLR) setting of a child is determined
      - posix_spawnattr_setcred()
        Set the user and group ID attributes in a spawn attributes object
      - posix_spawnattr_setcwd_np()
        Set the current working directory attribute in a spawn attributes object
      - posix_spawnattr_setflags()
        Set the POSIX flags in a spawn attributes object
      - posix_spawnattr_setpgroup()
        Set the process group attribute in a spawn attributes object
      - posix_spawnattr_setrunmask()
        Set the runmask attribute in a spawn attributes object
      - posix_spawnattr_setschedparam()
        Set the scheduling parameters attribute of a spawn attributes object
      - posix_spawnattr_setschedpolicy()
        Set the scheduling policy attribute of a spawn attributes object
      - posix_spawnattr_setsigdefault()
        Set the default signals attribute of a spawn attributes object
      - posix_spawnattr_setsigignore()
        Set the ignored signals attribute of a spawn attributes object
      - posix_spawnattr_setsigmask()
        Set the signal mask attribute of a spawn attributes object
      - posix_spawnattr_setstackmax()
        Set the maximum stack size attribute in a spawn attributes object
      - posix_spawnattr_settypeid()
        Set the type identifier of a spawn attributes object
      - posix_spawnattr_setxflags()
        Set the POSIX flags and the QNX OS extended flags in a spawn attributes object
      - posix_typed_mem_get_info()
        Get information about a typed memory object
      - posix_typed_mem_open()
        Open a typed memory object
      - pow(), powf(), powl()
        Raise a number to a given power
      - pread(), pread64()
        Read from a file without moving the file pointer
      - printf()
        Write formatted output to stdout
      - prlimit(), prlimit64()
        Set and get the limit on a system resource
      - procmgr_ability()
        Control a process's ability to perform certain operations
      - procmgr_ability_create()
        Create a process-manager ability
      - procmgr_ability_lookup()
        Look up a process-manager ability
      - procmgr_ability_name()
        Get the name of a custom ability
      - procmgr_daemon()
        Run a process in the background
      - procmgr_event_notify()
        Ask to be notified of system-wide events
      - procmgr_event_notify_add()
        Add a request to be notified of system-wide events
      - procmgr_event_notify_delete()
        Delete a request to be notified of system-wide events
      - procmgr_event_trigger(), procmgr_event_trigger_updateable()
        Trigger a system-wide event
      - procmgr_session(), procmgr_session_ext()
        Provide process manager session support
      - procmgr_set_type_id()
        Allows a function to change its own type identifier
      - procmgr_timer_tolerance()
        Get or set the default timer tolerance for a process
      - procmgr_value_current()
        Get the current value of an item being monitored
      - procmgr_value_notify_add()
        Add an event to be triggered when a monitored value crosses a trigger point
      - __progname
        The basename of the program being executed
      - pthread_abort()
        Unconditionally terminate the target thread
      - pthread_atfork()
        Register fork handlers
      - pthread_attr_destroy()
        Destroy a thread-attribute object
      - pthread_attr_getdetachstate()
        Get the thread detach state attribute
      - pthread_attr_getguardsize()
        Get the size of the thread's guard area
      - pthread_attr_getinheritsched()
        Get a thread's inherit-scheduling attribute
      - pthread_attr_getschedparam()
        Get the thread scheduling parameters attribute
      - pthread_attr_getschedpolicy()
        Get the thread scheduling policy attribute
      - pthread_attr_getscope()
        Get the thread contention scope attribute
      - pthread_attr_getstack()
        Get the thread-creation stack attributes
      - pthread_attr_getstackaddr()
        Get the thread stack address attribute
      - pthread_attr_getstacklazy()
        Get the thread lazy-stack attribute
      - pthread_attr_getstackprealloc()
        Get the amount of memory to preallocate for a thread's MAP_LAZY stack
      - pthread_attr_getstacksize()
        Get the thread stack-size attribute
      - pthread_attr_getsuspendstate_np()
        Get the thread suspend state attribute
      - pthread_attr_init()
        Initialize a thread-attribute object
      - pthread_attr_setdetachstate()
        Set the thread detach state attribute
      - pthread_attr_setguardsize()
        Set the size of the thread's guard area
      - pthread_attr_setinheritsched()
        Set the thread's inherit-scheduling attribute
      - pthread_attr_setschedparam()
        Set a thread's scheduling parameters attribute
      - pthread_attr_setschedpolicy()
        Set the thread scheduling policy attribute
      - pthread_attr_setscope()
        Set the thread contention scope attribute
      - pthread_attr_setstack()
        Set the thread-creation stack attributes
      - pthread_attr_setstackaddr()
        Set the thread stack address attribute
      - pthread_attr_setstacklazy()
        Set the thread lazy-stack attribute
      - pthread_attr_setstackprealloc()
        Set the amount of memory to preallocate for a thread's MAP_LAZY stack
      - pthread_attr_setstacksize()
        Set the thread stack-size attribute
      - pthread_attr_setsuspendstate_np()
        Set the thread suspend state attribute
      - pthread_barrier_destroy()
        Destroy a barrier object
      - pthread_barrier_init()
        Initialize a barrier object
      - pthread_barrier_wait()
        Synchronize participating threads at the barrier
      - pthread_barrierattr_destroy()
        Destroy a barrier-attributes object
      - pthread_barrierattr_getpshared()
        Get the value of a barrier's process-shared attribute
      - pthread_barrierattr_init()
        Initialize a barrier attributes object
      - pthread_barrierattr_setpshared()
        Set the value of a barrier's process-shared attribute
      - pthread_cancel()
        Cancel a thread
      - pthread_cleanup_pop()
        Pop a function off of a thread's cancellation-cleanup stack
      - pthread_cleanup_push()
        Push a function onto a thread's cancellation-cleanup stack
      - pthread_cluster_get_runmask()
        Validate a cluster name and provide its associated runmask
      - pthread_cluster_set()
        Set cluster characteristics for the calling thread
      - pthread_cluster_set_and_inherit()
        Set cluster characteristics for the calling thread and for its children to inherit
      - pthread_cond_broadcast()
        Unblock threads waiting on a condition
      - pthread_cond_clockwait()
        Wait on a condition variable, with a time limit measured against a specific clock
      - pthread_cond_destroy()
        Destroy a condition variable
      - pthread_cond_init()
        Initialize a condition variable
      - pthread_cond_signal()
        Unblock a thread that's waiting on a condition variable
      - pthread_cond_timedwait()
        Wait on a condition variable, with a time limit
      - pthread_cond_wait()
        Wait on a condition variable
      - pthread_condattr_destroy()
        Destroy a condition-variable attribute object
      - pthread_condattr_getclock()
        Get the clock attribute from a condition-variable attribute object
      - pthread_condattr_getpshared()
        Get the process-shared attribute from a condition variable attribute object
      - pthread_condattr_init()
        Initialize the attribute object for creating condition variables
      - pthread_condattr_setclock()
        Set the clock attribute of a condition-variable attribute object
      - pthread_condattr_setpshared()
        Set the process-shared attribute in a condition variable attribute object
      - pthread_create()
        Create a thread
      - pthread_detach()
        Detach a thread from a process
      - pthread_equal()
        Compare two thread IDs
      - pthread_exit()
        Terminate a thread
      - pthread_getconcurrency()
        Get the level of thread concurrency
      - pthread_getcpuclockid()
        Return the clock ID of the CPU-time clock from a specified thread
      - pthread_getname_np()
        Retrieve the name of a thread
      - pthread_getschedparam()
        Get a thread's scheduling parameters
      - pthread_getspecific()
        Get a thread-specific data value
      - pthread_join()
        Join thread
      - pthread_key_create()
        Create a thread-specific data key
      - pthread_key_delete()
        Delete a thread-specific data key
      - pthread_kill()
        Send a signal to a thread
      - pthread_mutex_clocklock()
        Lock a mutex with a time limit measured against a specific clock
      - pthread_mutex_consistent()
        Mark as consistent the state that's protected by a mutex
      - pthread_mutex_destroy()
        Destroy a mutex
      - pthread_mutex_getprioceiling()
        Get a mutex's priority ceiling
      - pthread_mutex_init()
        Initialize a mutex
      - pthread_mutex_lock()
        Lock a mutex
      - pthread_mutex_setprioceiling()
        Set a mutex's priority ceiling
      - pthread_mutex_timedlock(), pthread_mutex_timedlock_monotonic()
        Lock a mutex, with a time limit
      - pthread_mutex_trylock()
        Attempt to lock a mutex
      - pthread_mutex_unlock()
        Unlock a mutex
      - pthread_mutex_wakeup_np()
        Unblock any threads that are waiting on a mutex
      - pthread_mutexattr_destroy()
        Destroy mutex attribute object
      - pthread_mutexattr_getprioceiling()
        Get the priority ceiling of a mutex attribute object
      - pthread_mutexattr_getprotocol()
        Get a mutex's scheduling protocol
      - pthread_mutexattr_getpshared()
        Get the process-shared attribute from a mutex attribute object
      - pthread_mutexattr_getrecursive()
        Get the recursive attribute from a mutex attribute object
      - pthread_mutexattr_getrobust()
        Get the robust attribute from a mutex attribute object
      - pthread_mutexattr_gettype()
        Get a mutex type
      - pthread_mutexattr_getwakeup_np()
        Get the wake-up attribute of a mutex
      - pthread_mutexattr_init()
        Initialize a mutex attribute object
      - pthread_mutexattr_setprioceiling()
        Set the priority ceiling of a mutex attribute object
      - pthread_mutexattr_setprotocol()
        Set a mutex's scheduling protocol
      - pthread_mutexattr_setpshared()
        Set the process-shared attribute in mutex attribute object
      - pthread_mutexattr_setrecursive()
        Set the recursive attribute in mutex attribute object
      - pthread_mutexattr_setrobust()
        Set the robust attribute in a mutex attribute object
      - pthread_mutexattr_settype()
        Set a mutex type
      - pthread_mutexattr_setwakeup_np()
        Set the wake-up attribute of a mutex
      - pthread_once()
        Dynamic package initialization
      - pthread_rwlock_clockrdlock()
        Lock a read-write lock for reading with a time limit measured against a clock
      - pthread_rwlock_clockwrlock()
        Lock a read-write lock for writing with a time limit measured against a specific clock
      - pthread_rwlock_destroy()
        Destroy a read-write lock
      - pthread_rwlock_init()
        Initialize a read-write lock
      - pthread_rwlock_rdlock()
        Acquire a shared read lock on a read-write lock
      - pthread_rwlock_timedrdlock()
        Lock a read-write lock for reading
      - pthread_rwlock_timedwrlock()
        Lock a read-write lock for writing
      - pthread_rwlock_tryrdlock()
        Attempt to acquire a shared lock on a read-write lock
      - pthread_rwlock_trywrlock()
        Attempt to acquire an exclusive lock on a read-write lock
      - pthread_rwlock_unlock()
        Unlock a read-write lock
      - pthread_rwlock_wrlock()
        Acquire an exclusive write lock on a read-write lock
      - pthread_rwlockattr_destroy()
        Destroy a read-write lock attribute object
      - pthread_rwlockattr_getpshared()
        Get the process-shared attribute of a read-write lock attribute object
      - pthread_rwlockattr_init()
        Create a read-write lock attribute object
      - pthread_rwlockattr_setpshared()
        Set the process-shared attribute of a read-write lock attribute object
      - pthread_self()
        Get the calling thread's ID
      - pthread_setcancelstate()
        Set a thread's cancellation state
      - pthread_setcanceltype()
        Set a thread's cancellation type
      - pthread_setconcurrency()
        Set the concurrency level for a thread
      - pthread_setname_np()
        Name a thread
      - pthread_setschedparam()
        Set thread scheduling parameters
      - pthread_setschedprio()
        Set a thread's priority
      - pthread_setspecific()
        Set a thread-specific data value
      - pthread_sigmask()
        Modify or examine a thread's signal-blocked mask
      - pthread_spin_destroy()
        Destroy a thread spinlock
      - pthread_spin_init()
        Initialize a thread spinlock
      - pthread_spin_lock()
        Lock a thread spinlock
      - pthread_spin_trylock()
        Try to lock a thread spinlock
      - pthread_spin_unlock()
        Unlock a thread spinlock
      - pthread_testcancel()
        Test thread cancellation
      - pthread_timedjoin(), pthread_timedjoin_monotonic()
        Join a thread, with a time limit
      - ptsname()
        Get the name of a slave pseudo-terminal device
      - ptsname_r()
        Get the name of a slave pseudo-terminal device
      - _pulse
        Structure that describes a pulse
      - pulse_attach()
        Attach a handler function to a pulse code
      - pulse_detach()
        Detach a handler function from a pulse code
      - putc()
        Write a character to a stream
      - putc_unlocked()
        Write a character to an output stream
      - putchar()
        Write a character to standard output
      - putchar_unlocked()
        Write a character to stdout
      - putenv()
        Add, change or delete an environment variable
      - puts()
        Write a string to stdout
      - putspent()
        Put an entry into the shadow password database
      - pututline()
        Write an entry in the user-information file
      - putw()
        Put a word on a stream
      - putwc()
        Write a wide character to a stream
      - putwchar()
        Write a wide character to a stdout
      - pwrite(), pwrite64()
        Write into a file without changing the file pointer
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  - QNX Helpers Developer's Guide
    These libraries provide QNX helpers, including helpers that assist with logging, string conversion, and number and type sizes.
  - SPI Framework Technote
  - Utilities Reference
  - WPA Control Interface Reference
    This document provides a reference for the Wi-Fi Protected Access (WPA) control interface, which provides a C API for the WPA/IEEE 802.11i protocols in Wi-Fi client stations. Application developers who want to control WPA operations and get associated status and event data should read this reference.
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This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

pthread_rwlockattr_getpshared()

QNX SDP8.0C Library ReferenceAPIDeveloper

Get the process-shared attribute of a read-write lock attribute object

Synopsis:

#include <pthread.h>

int pthread_rwlockattr_getpshared( 
       const pthread_rwlockattr_t* attr,
       int* pshared );

Arguments:

attr: A pointer to the pthread_rwlockattr_t object that you want to get the attribute from.
pshared: A pointer to a location where the function can store the process-shared attribute.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The pthread_rwlockattr_getpshared() function gets the process-shared attribute for the read-write lock attribute object specified by attr, storing it in pshared. The possible values are:

PTHREAD_PROCESS_SHARED — any thread with access to the read-write lock object's memory can operate it, even if those threads are in different processes.
PTHREAD_PROCESS_PRIVATE — access is limited to threads in the current process.

Note:

If you started procnto with the -s option, set the process-shared attribute to PTHREAD_PROCESS_SHARED for any read-write locks that are shared between processes. For more information, see Safely sharing mutexes, barriers, and reader/writer locks between processes in the QNX OS Microkernel chapter of the System Architecture guide.

Returns:

EOK: Success.
EINVAL: The read-write lock attribute object specified by attr is invalid.

Classification:

POSIX 1003.1 TSH


Safety:
Cancellation point	No
Signal handler	Yes
Thread	Yes

Page updated: August 09, 2024