posix_fallocate


SYNOPSIS
       #include <fcntl.h>

       int posix_fallocate(int fd, off_t offset, off_t len);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       posix_fallocate():
           _XOPEN_SOURCE >= 600 || _POSIX_C_SOURCE >= 200112L

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 VALUE
       posix_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 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.

VERSIONS
       posix_fallocate() is available since glibc 2.1.94.

CONFORMING TO
       POSIX.1-2001.

       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 ALSO
       fallocate(2), lseek(2), posix_fadvise(2)

COLOPHON
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