получить и установить атрибуты стека (get and set stack attributes)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
pthread_attr_getstack, pthread_attr_setstack — get and set stack
attributes
Синопсис (Synopsis)
#include <pthread.h>
int pthread_attr_getstack(const pthread_attr_t *restrict attr,
void **restrict stackaddr, size_t *restrict stacksize);
int pthread_attr_setstack(pthread_attr_t *attr, void *stackaddr,
size_t stacksize);
Описание (Description)
The pthread_attr_getstack() and pthread_attr_setstack()
functions, respectively, shall get and set the thread creation
stack attributes stackaddr and stacksize in the attr object.
The stack attributes specify the area of storage to be used for
the created thread's stack. The base (lowest addressable byte) of
the storage shall be stackaddr, and the size of the storage shall
be stacksize bytes. The stacksize shall be at least
{PTHREAD_STACK_MIN}. The pthread_attr_setstack() function may
fail with [EINVAL] if stackaddr does not meet implementation-
defined alignment requirements. All pages within the stack
described by stackaddr and stacksize shall be both readable and
writable by the thread.
If the pthread_attr_getstack() function is called before the
stackaddr attribute has been set, the behavior is unspecified.
The behavior is undefined if the value specified by the attr
argument to pthread_attr_getstack() or pthread_attr_setstack()
does not refer to an initialized thread attributes object.
Возвращаемое значение (Return value)
Upon successful completion, these functions shall return a value
of 0; otherwise, an error number shall be returned to indicate
the error.
The pthread_attr_getstack() function shall store the stack
attribute values in stackaddr and stacksize if successful.
Ошибки (Error)
The pthread_attr_setstack() function shall fail if:
EINVAL The value of stacksize is less than {PTHREAD_STACK_MIN} or
exceeds an implementation-defined limit.
The pthread_attr_setstack() function may fail if:
EINVAL The value of stackaddr does not have proper alignment to
be used as a stack, or ((char *)stackaddr + stacksize)
lacks proper alignment.
EACCES The stack page(s) described by stackaddr and stacksize are
not both readable and writable by the thread.
These functions shall not return an error code of [EINTR].
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
These functions are appropriate for use by applications in an
environment where the stack for a thread must be placed in some
particular region of memory.
While it might seem that an application could detect stack
overflow by providing a protected page outside the specified
stack region, this cannot be done portably. Implementations are
free to place the thread's initial stack pointer anywhere within
the specified region to accommodate the machine's stack pointer
behavior and allocation requirements. Furthermore, on some
architectures, such as the IA‐64, ``overflow'' might mean that
two separate stack pointers allocated within the region will
overlap somewhere in the middle of the region.
After a successful call to pthread_attr_setstack(), the storage
area specified by the stackaddr parameter is under the control of
the implementation, as described in Section 2.9.8, Use of
Application-Managed Thread Stacks.
The specification of the stackaddr attribute presents several
ambiguities that make portable use of these functions impossible.
For example, the standard allows implementations to impose
arbitrary alignment requirements on stackaddr. Applications
cannot assume that a buffer obtained from malloc() is suitably
aligned. Note that although the stacksize value passed to
pthread_attr_setstack() must satisfy alignment requirements, the
same is not true for pthread_attr_setstacksize() where the
implementation must increase the specified size if necessary to
achieve the proper alignment.
Обоснование (Rationale)
If an implementation detects that the value specified by the attr
argument to pthread_attr_getstack() or pthread_attr_setstack()
does not refer to an initialized thread attributes object, it is
recommended that the function should fail and report an [EINVAL]
error.
Будущие направления (Future directions)
None.
Смотри также (See also)
pthread_attr_destroy(3p), pthread_attr_getdetachstate(3p),
pthread_attr_getstacksize(3p), pthread_create(3p)
The Base Definitions volume of POSIX.1‐2017, limits.h(0p),
pthread.h(0p)
