POSIX_FALLOCATE(3) Linux Programmer's Manual POSIX_FALLOCATE(3)NAMEposix_fallocate - allocate file space
int posix_fallocate(int fd, off_t offset, off_t len);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE >= 600 || _POSIX_C_SOURCE >= 200112L
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.
EBADF fd is not a valid file descriptor, or is not opened for writing.
EFBIG offset+len exceeds the maximum file size.
EINVAL offset was less than 0, or len was less than or equal to 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.
VERSIONSposix_fallocate() is available since glibc 2.1.94.
POSIX.1-2008 says that an implementation shall give the EINVAL error if
len was 0, or offset was less than 0. POSIX.1-2001 says that an imple‐
mentation shall give the EINVAL error if len is less than 0, or offset
was less than 0, and may give the error if len equals zero.
SEE ALSOfallocate(1), fallocate(2), lseek(2), posix_fadvise(2)COLOPHON
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GNU 2013-02-12 POSIX_FALLOCATE(3)