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       posix_fallocate - allocate file space


       #define _XOPEN_SOURCE 600
       #include <fcntl.h>

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


       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.


       posix_fallocate() returns zero  on  success,  or  an  error  number  on
       failure.  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 of file descriptor.


       posix_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
       implementation  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.


       fallocate(2), lseek(2), posix_fadvise(2), feature_test_macros(7)


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