man3/pthread_mutexattr_getpshared.3

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  25 .TH PTHREAD_MUTEXATTR_GETPSHARED 3 2017-09-13 "Linux" "Linux Programmer's Manual"
  26 .SH NAME
  27 pthread_mutexattr_getpshared, pthread_mutexattr_setpshared \- get/set
  28 process-shared mutex attribute
  29 .SH SYNOPSIS
  30 .nf
  31 .B #include <pthread.h>
  32 .PP
  33 .BI "int pthread_mutexattr_getpshared(const pthread_mutexattr_t *" attr ,
  34 .BI "                                 int *" pshared );
  35 .BI "int pthread_mutexattr_setpshared(pthread_mutexattr_t *" attr ,
  36 .BI "                                 int " pshared );
  37 .fi
  38 .PP
  39 Compile and link with \fI\-pthread\fP.
  40 .SH DESCRIPTION
  41 These functions get and set the process-shared attribute
  42 in a mutex attributes object.
  43 This attribute must be appropriately set to ensure correct,
  44 efficient operation of a mutex created using this attributes object.
  45 .PP
  46 The process-shared attribute can have one of the following values:
  47 .TP
  48 .B PTHREAD_PROCESS_PRIVATE
  49 Mutexes created with this attributes object are to be shared
  50 only among threads in the same process that initialized the mutex.
  51 This is the default value for the process-shared mutex attribute.
  52 .TP
  53 .B PTHREAD_PROCESS_SHARED
  54 Mutexes created with this attributes object can be shared between
  55 any threads that have access to the memory containing the object,
  56 including threads in different processes.
  57 .PP
  58 .BR pthread_mutexattr_getpshared ()
  59 places the value of the process-shared attribute of
  60 the mutex attributes object referred to by
  61 .IR attr
  62 in the location pointed to by
  63 .IR pshared .
  64 .PP
  65 .BR pthread_mutexattr_setpshared ()
  66 sets the value of the process-shared attribute of
  67 the mutex attributes object referred to by
  68 .IR attr
  69 to the value specified in
  70 .BR pshared .
  71 .PP
  72 If
  73 .I attr
  74 does not refer to an initialized mutex attributes object,
  75 the behavior is undefined.
  76 .SH RETURN VALUE
  77 On success, these functions return 0.
  78 On error, they return a positive error number.
  79 .SH ERRORS
  80 .BR pthread_mutexattr_setpshared ()
  81 can fail with the following errors:
  82 .TP
  83 .B EINVAL
  84 The value specified in
  85 .I pshared
  86 is invalid.
  87 .TP
  88 .B ENOTSUP
  89 .I pshared is
  90 .BR PTHREAD_PROCESS_SHARED
  91 but the implementation does not support process-shared mutexes.
  92 .SH CONFORMING TO
  93 POSIX.1-2001, POSIX.1-2008.
  94 .SH SEE ALSO
  95 .ad l
  96 .nh
  97 .BR pthread_mutexattr_init (3),
  98 .BR pthreads (7)