|POSIX_FALLOCATE(2)||System Calls Manual||POSIX_FALLOCATE(2)|
pre-allocate storage for a range in a file
Standard C Library (libc, -lc)
fd, off_t offset,
Required storage for the range offset to
offset + len in the file
referenced by fd is guaranteed to be allocated upon
successful return. That is, if
returns successfully, subsequent writes to the specified file data will not
fail due to lack of free space on the file system storage media. Any
existing file data in the specified range is unmodified. If
offset + len is beyond the
current file size, then
adjust the file size to offset +
len. Otherwise, the file size will not be changed.
Space allocated by
will be freed by a successful call to creat(2) or
open(2) that truncates the size of the file. Space
posix_fallocate() may be freed by a
successful call to ftruncate(2) that reduces the file size
to a size smaller than offset +
zero. It returns an error on failure, without setting
Possible failure conditions:
- The fd argument is not a valid file descriptor.
- The fd argument references a file that was opened without write permission.
- The value of offset + len is greater than the maximum file size.
- A signal was caught during execution.
- The len argument was less than or equal to zero, the offset argument was less than zero, or the operation is not supported by the file system.
- An I/O error occurred while reading from or writing to a file system.
- Corrupted data was detected while reading from the file system.
- The fd argument does not refer to a regular file.
- There is insufficient free space remaining on the file system storage media.
- The file descriptor fd has insufficient rights.
- The fd argument is associated with a pipe or FIFO.
posix_fallocate() system call conforms
to IEEE Std 1003.1-2004
posix_fallocate() function appeared in
posix_fallocate() and this manual page
were initially written by Matthew Fleming
|March 30, 2020||Debian|