.\" Automatically generated by Pandoc 2.9.2.1
.\"
.TH "" "" "2023-05-26" "PMDK - " "PMDK Programmer's Manual"
.hy
.\" SPDX-License-Identifier: BSD-3-Clause
.\" Copyright 2019-2020, Intel Corporation
.SH NAME
.PP
\f[B]pmem2_source_alignment\f[R]() - returns data source alignment
.SH SYNOPSIS
.IP
.nf
\f[C]
#include <libpmem2.h>

struct pmem2_source;
int pmem2_source_alignment(const struct pmem2_source *source, size_t *alignment);
\f[R]
.fi
.SH DESCRIPTION
.PP
The \f[B]pmem2_source_alignment\f[R]() function retrieves the alignment
of offset and length needed for \f[B]pmem2_map_new\f[R](3) to succeed.
The alignment is stored in \f[I]*alignment\f[R].
.SH RETURN VALUE
.PP
The \f[B]pmem2_source_alignment\f[R]() function returns 0 on success.
If the function fails, the \f[I]*alignment\f[R] variable is left
unmodified and a negative error code is returned.
.SH ERRORS
.PP
The \f[B]pmem2_source_alignment\f[R]() can fail with the following
errors:
.PP
On all systems:
.IP \[bu] 2
\f[B]PMEM2_E_INVALID_ALIGNMENT_VALUE\f[R] - operating system returned
unexpected alignment value (eg.
it is not a power of two).
.PP
on Linux:
.IP \[bu] 2
\f[B]PMEM2_E_INVALID_FILE_TYPE\f[R] - file descriptor points to a
character device other than Device DAX.
.IP \[bu] 2
\f[B]PMEM2_E_INVALID_ALIGNMENT_FORMAT\f[R] - kernel query for Device DAX
alignment returned data in invalid format.
.IP \[bu] 2
-\f[B]errno\f[R] set by failing \f[B]fstat\f[R](2), while trying to
validate the file descriptor.
.IP \[bu] 2
-\f[B]errno\f[R] set by failing \f[B]realpath\f[R](3), while trying to
determine whether fd points to a Device DAX.
.IP \[bu] 2
-\f[B]errno\f[R] set by failing \f[B]read\f[R](2), while trying to
determine Device DAX\[cq]s alignment.
.IP \[bu] 2
-\f[B]errno\f[R] set by failing \f[B]strtoull\f[R](3), while trying to
determine Device DAX\[cq]s alignment.
.PP
On FreeBSD:
.IP \[bu] 2
\f[B]PMEM2_E_INVALID_FILE_TYPE\f[R] - file descriptor points to a
directory, block device, pipe, socket, or character device.
.IP \[bu] 2
-\f[B]errno\f[R] set by failing \f[B]fstat\f[R](2), while trying to
validate the file descriptor.
.SH SEE ALSO
.PP
\f[B]errno\f[R](3), \f[B]fstat\f[R](2), \f[B]realpath\f[R](3),
\f[B]read\f[R](2), \f[B]strtoull\f[R](3), \f[B]pmem2_config_new\f[R](3),
\f[B]pmem2_source_from_handle\f[R](3),
\f[B]pmem2_source_from_fd\f[R](3), \f[B]libpmem2\f[R](7) and
\f[B]<https://pmem.io>\f[R]