pthread_attr_setstack, pthread_attr_getstack - set/get stack attributes in
thread attributes object
POSIX threads library (
libpthread,
-lpthread)
#include <pthread.h>
int pthread_attr_setstack(pthread_attr_t *attr,
void stackaddr[.stacksize],
size_t stacksize);
int pthread_attr_getstack(const pthread_attr_t *restrict attr,
void **restrict stackaddr,
size_t *restrict stacksize);
pthread_attr_getstack(),
pthread_attr_setstack():
_POSIX_C_SOURCE >= 200112L
The
pthread_attr_setstack() function sets the stack address and stack
size attributes of the thread attributes object referred to by
attr to
the values specified in
stackaddr and
stacksize, respectively.
These attributes specify the location and size of the stack that should be
used by a thread that is created using the thread attributes object
attr.
stackaddr should point to the lowest addressable byte of a buffer of
stacksize bytes that was allocated by the caller. The pages of the
allocated buffer should be both readable and writable.
The
pthread_attr_getstack() function returns the stack address and stack
size attributes of the thread attributes object referred to by
attr in
the buffers pointed to by
stackaddr and
stacksize, respectively.
On success, these functions return 0; on error, they return a nonzero error
number.
pthread_attr_setstack() can fail with the following error:
- EINVAL
-
stacksize is less than PTHREAD_STACK_MIN
(16384) bytes. On some systems, this error may also occur if
stackaddr or stackaddr + stacksize is not
suitably aligned.
POSIX.1 also documents an
EACCES error if the stack area described by
stackaddr and
stacksize is not both readable and writable by the
caller.
These functions are provided since glibc 2.2.
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
pthread_attr_setstack (), pthread_attr_getstack () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008.
These functions are provided for applications that must ensure that a thread's
stack is placed in a particular location. For most applications, this is not
necessary, and the use of these functions should be avoided. (Use
pthread_attr_setstacksize(3) if an application simply requires a stack
size other than the default.)
When an application employs
pthread_attr_setstack(), it takes over the
responsibility of allocating the stack. Any guard size value that was set
using
pthread_attr_setguardsize(3) is ignored. If deemed necessary, it
is the application's responsibility to allocate a guard area (one or more
pages protected against reading and writing) to handle the possibility of
stack overflow.
The address specified in
stackaddr should be suitably aligned: for full
portability, align it on a page boundary (
sysconf(_SC_PAGESIZE)).
posix_memalign(3) may be useful for allocation. Probably,
stacksize should also be a multiple of the system page size.
If
attr is used to create multiple threads, then the caller must change
the stack address attribute between calls to
pthread_create(3);
otherwise, the threads will attempt to use the same memory area for their
stacks, and chaos will ensue.
See
pthread_attr_init(3).
mmap(2),
mprotect(2),
posix_memalign(3),
pthread_attr_init(3),
pthread_attr_setguardsize(3),
pthread_attr_setstackaddr(3),
pthread_attr_setstacksize(3),
pthread_create(3),
pthreads(7)