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msem_lock(3)
NAME
  msem_lock - Lock a semaphore

SYNOPSIS
  #include <sys/mman.h>

  int msem_lock(
	  msemaphore *sem,
	  int condition );

LIBRARY
  Standard C Library (libc)

PARAMETERS
  sem Points to an msemaphore structure which specifies the semaphore to be
      locked.

  condition
      Determines whether the msem_lock() function waits for a currently
      locked semaphore to unlock.

DESCRIPTION
  The msem_lock() function attempts to lock a binary semaphore.

  If the semaphore is not currently locked, it is locked and the msem_lock()
  function returns successfully.

  If the semaphore is currently locked, and the condition parameter is
  MSEM_IF_NOWAIT, then the msem_lock() function returns with an error. If the
  semaphore is currently locked, and the condition parameter is 0 (zero),
  then msem_lock() will not return until either the calling process is able
  to successfully lock the semaphore, or an error condition occurs.

  All calls to msem_lock() and msem_unlock() by multiple processes sharing a
  common msemaphore structure behave as if the calls were serialized.

  If the msemaphore structure contains any value not resulting from a call to
  msem_init() followed by a (possibly empty) sequence of calls to msem_lock()
  and msem_unlock(), the results are undefined. The address of an msemaphore
  structure may be significant. If the msemaphore structure contains any
  value copied from an msemaphore structure at a different address, the
  result is undefined.

NOTES
  AES Support Level:
      Trial use

RETURN VALUES
  On successful completion, the msem_lock() function returns 0 (zero). On
  error, the msem_lock() function returns -1 and sets errno to indicate the
  error.

ERRORS
  If the msem_lock() function fails, errno may be set to one of the following
  values:

  [EAGAIN]
      MSEM_IF_NOWAIT was specified and the semaphore was already locked.

  [EINVAL]
      The sem parameter points to an msemaphore structure which specifies a
      semaphore which has been removed, or the condition parameter is
      invalid.

  [EINTR]
      The msem_lock() function was interrupted by a signal which was caught.

SEE ALSO
  Functions: msem_init(3), msem_remove(3), msem_unlock(3)

Index for Section 3

Alphabetical listing for M

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