man3/pthread_attr_setstack.3

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  26 .TH PTHREAD_ATTR_SETSTACK 3 2017-09-15 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 pthread_attr_setstack, pthread_attr_getstack \- set/get stack
  29 attributes in thread attributes object
  30 .SH SYNOPSIS
  31 .nf
  32 .B #include <pthread.h>
  33 .PP
  34 .BI "int pthread_attr_setstack(pthread_attr_t *" attr ,
  35 .BI "                          void *" stackaddr ", size_t " stacksize );
  36 .BI "int pthread_attr_getstack(const pthread_attr_t *" attr ,
  37 .BI "                          void **" stackaddr ", size_t *" stacksize );
  38 .PP
  39 Compile and link with \fI\-pthread\fP.
  40 .fi
  41 .PP
  42 .in -4n
  43 Feature Test Macro Requirements for glibc (see
  44 .BR feature_test_macros (7)):
  45 .in
  46 .PP
  47 .ad l
  48 .BR pthread_attr_getstack (),
  49 .BR pthread_attr_setstack ():
  50 .RS 4
  51 _POSIX_C_SOURCE\ >=\ 200112L
  52 .RE
  53 .ad b
  54 .SH DESCRIPTION
  55 The
  56 .BR pthread_attr_setstack ()
  57 function sets the stack address and stack size attributes of the
  58 thread attributes object referred to by
  59 .I attr
  60 to the values specified in
  61 .IR stackaddr
  62 and
  63 .IR stacksize ,
  64 respectively.
  65 These attributes specify the location and size of the stack that should
  66 be used by a thread that is created using the thread attributes object
  67 .IR attr .
  68 .PP
  69 .I stackaddr
  70 should point to the lowest addressable byte of a buffer of
  71 .I stacksize
  72 bytes that was allocated by the caller.
  73 The pages of the allocated buffer should be both readable and writable.
  74 .PP
  75 The
  76 .BR pthread_attr_getstack ()
  77 function returns the stack address and stack size attributes of the
  78 thread attributes object referred to by
  79 .I attr
  80 in the buffers pointed to by
  81 .IR stackaddr
  82 and
  83 .IR stacksize ,
  84 respectively.
  85 .SH RETURN VALUE
  86 On success, these functions return 0;
  87 on error, they return a nonzero error number.
  88 .SH ERRORS
  89 .BR pthread_attr_setstack ()
  90 can fail with the following error:
  91 .TP
  92 .B EINVAL
  93 .I stacksize
  94 is less than
  95 .BR PTHREAD_STACK_MIN
  96 (16384) bytes.
  97 On some systems, this error may also occur if
  98 .IR stackaddr
  99 or
 100 .IR "stackaddr\ +\ stacksize"
 101 is not suitably aligned.
 102 .PP
 103 POSIX.1 also documents an
 104 .BR EACCES
 105 error if the stack area described by
 106 .I stackaddr
 107 and
 108 .I stacksize
 109 is not both readable and writable by the caller.
 110 .SH VERSIONS
 111 These functions are provided by glibc since version 2.2.
 112 .SH ATTRIBUTES
 113 For an explanation of the terms used in this section, see
 114 .BR attributes (7).
 115 .TS
 116 allbox;
 117 lbw24 lb lb
 118 l l l.
 119 Interface       Attribute       Value
 120 T{
 121 .BR pthread_attr_setstack (),
 122 .BR pthread_attr_getstack ()
 123 T}      Thread safety   MT-Safe
 124 .TE
 125 .SH CONFORMING TO
 126 POSIX.1-2001, POSIX.1-2008.
 127 .SH NOTES
 128 These functions are provided for applications that must ensure that
 129 a thread's stack is placed in a particular location.
 130 For most applications, this is not necessary,
 131 and the use of these functions should be avoided.
 132 (Use
 133 .BR pthread_attr_setstacksize (3)
 134 if an application simply requires a stack size other than the default.)
 135 .PP
 136 When an application employs
 137 .BR pthread_attr_setstack (),
 138 it takes over the responsibility of allocating the stack.
 139 Any guard size value that was set using
 140 .BR pthread_attr_setguardsize (3)
 141 is ignored.
 142 If deemed necessary,
 143 it is the application's responsibility to allocate a guard area
 144 (one or more pages protected against reading and writing)
 145 to handle the possibility of stack overflow.
 146 .PP
 147 The address specified in
 148 .I stackaddr
 149 should be suitably aligned:
 150 for full portability, align it on a page boundary
 151 .RI ( sysconf(_SC_PAGESIZE) ).
 152 .BR posix_memalign (3)
 153 may be useful for allocation.
 154 Probably,
 155 .IR stacksize
 156 should also be a multiple of the system page size.
 157 .PP
 158 If
 159 .I attr
 160 is used to create multiple threads, then the caller must change the
 161 stack address attribute between calls to
 162 .BR pthread_create (3);
 163 otherwise, the threads will attempt to use the same memory area
 164 for their stacks, and chaos will ensue.
 165 .SH EXAMPLE
 166 See
 167 .BR pthread_attr_init (3).
 168 .SH SEE ALSO
 169 .ad l
 170 .nh
 171 .BR mmap (2),
 172 .BR mprotect (2),
 173 .BR posix_memalign (3),
 174 .BR pthread_attr_init (3),
 175 .BR pthread_attr_setguardsize (3),
 176 .BR pthread_attr_setstackaddr (3),
 177 .BR pthread_attr_setstacksize (3),
 178 .BR pthread_create (3),
 179 .BR pthreads (7)