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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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POSIX_FALLOCATE(3P) POSIX Programmer's Manual POSIX_FALLOCATE(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.
posix_fallocate — file space control (ADVANCED REALTIME)
#include <fcntl.h>
int posix_fallocate(int fd, off_t offset, off_t len);
The posix_fallocate() function shall ensure that any required
storage for regular file data starting at offset and continuing
for len bytes is allocated on the file system storage media. If
posix_fallocate() returns successfully, subsequent writes to the
specified file data shall not fail due to the lack of free space
on the file system storage media.
If the offset+len is beyond the current file size, then
posix_fallocate() shall adjust the file size to offset+len.
Otherwise, the file size shall not be changed.
It is implementation-defined whether a previous posix_fadvise()
call influences allocation strategy.
Space allocated via posix_fallocate() shall be freed by a
successful call to creat() or open() that truncates the size of
the file. Space allocated via posix_fallocate() may be freed by a
successful call to ftruncate() that reduces the file size to a
size smaller than offset+len.
Upon successful completion, posix_fallocate() shall return zero;
otherwise, an error number shall be returned to indicate the
error.
The posix_fallocate() function shall fail if:
EBADF The fd argument is not a valid file descriptor.
EBADF The fd argument references a file that was opened without
write permission.
EFBIG The value of offset+len is greater than the maximum file
size.
EINTR A signal was caught during execution.
EINVAL The len argument is less than zero, or the offset argument
is less than zero, or the underlying file system does not
support this operation.
EIO An I/O error occurred while reading from or writing to a
file system.
ENODEV The fd argument does not refer to a regular file.
ENOSPC There is insufficient free space remaining on the file
system storage media.
ESPIPE The fd argument is associated with a pipe or FIFO.
The posix_fallocate() function may fail if:
EINVAL The len argument is zero.
The following sections are informative.
None.
The posix_fallocate() function is part of the Advisory
Information option and need not be provided on all
implementations.
None.
None.
creat(3p), ftruncate(3p), open(3p), unlink(3p)
The Base Definitions volume of POSIX.1‐2017, fcntl.h(0p)
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 http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 POSIX_FALLOCATE(3P)
Pages that refer to this page: fcntl.h(0p)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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