POSIX_FALLOCATE(3) Linux Programmer's Manual POSIX_FALLOCATE(3)NAMEposix_fallocate - allocate file space
SYNOPSIS
#define _XOPEN_SOURCE 600
#include <stdlib.h>
int posix_fallocate(int fd, off_t offset, off_t len);
DESCRIPTION
The function posix_fallocate() ensures that disk space is allocated for
the file referred to by the descriptor fd for the bytes in the range
starting at offset and continuing for len bytes. After a successful
call to posix_fallocate(), subsequent writes to bytes in the specified
range are guaranteed not to fail because of lack of disk space.
If the size of the file is less than offset+len, then the file is
increased to this size; otherwise the file size is left unchanged.
RETURN VALUEposix_fallocate() returns zero on success, or an error number on fail‐
ure. Note that errno is not set.
ERRORS
EBADF fd is not a valid file descriptor, or is not opened for writing.
EFBIG offset+len exceeds the maximum file size.
EINVAL offset or len was less than 0.
ENODEV fd does not refer to a regular file.
ENOSPC There is not enough space left on the device containing the file
referred to by fd.
ESPIPE fd refers to a pipe of file descriptor.
AVAILABILITYposix_fallocate() is available since glibc 2.1.94.
CONFORMING TO
POSIX.1-2001.
SEE ALSOlseek(2), posix_fadvise(2)GNU 2006-03-01 POSIX_FALLOCATE(3)
