Section: POSIX Programmer's Manual (3P)
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.
--- query typed memory information
int posix_typed_mem_get_info(int fildes,
struct posix_typed_mem_info *info);
function shall return, in the
field of the
structure pointed to by
the maximum length which may be successfully allocated by the typed
memory object designated by
This maximum length shall take into account the flag
POSIX_TYPED_MEM_ALLOCATE or POSIX_TYPED_MEM_ALLOCATE_CONTIG specified
when the typed memory object represented by
was opened. The maximum length is dynamic; therefore, the value
returned is valid only while the current mapping of the corresponding
typed memory pool remains unchanged.
represents a typed memory object opened with neither the
POSIX_TYPED_MEM_ALLOCATE flag nor the POSIX_TYPED_MEM_ALLOCATE_CONTIG
flag specified, the returned value of info->posix_tmi_length
function may return additional implementation-defined information in
other fields of the
structure pointed to by
If the memory object specified by
is not a typed memory object, then the behavior of this function is
Upon successful completion, the
function shall return zero; otherwise, the corresponding error status
value shall be returned.
function shall fail if:
argument is not a valid open file descriptor.
argument is not connected to a memory object supported by this
This function shall not return an error code of
The following sections are informative.
An application that needs to allocate a block of typed memory with
length dependent upon the amount of memory currently available must
either query the typed memory object to obtain the amount available, or
attempting to guess an appropriate length. While the latter method is
existing practice with
it is awkward and imprecise. The
function allows an application to immediately determine available
memory. This is particularly important for typed memory objects that
may in some cases be scarce resources. Note that when a typed memory
pool is a shared resource, some form of mutual-exclusion or
synchronization may be required while typed memory is being queried and
allocated to prevent race conditions.
function is not suitable for this purpose. We realize that
implementations may wish to provide other attributes of typed memory
objects (for example, alignment requirements, page size, and so on).
function returns a structure which is not extensible and, furthermore,
contains substantial information that is inappropriate for typed memory
The Base Definitions volume of POSIX.1-2017,
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
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