eadahead

SYNOPSIS

      #include 
 
      ssize_t readahead(int fd, off64_t *offset, size_t count);

DESCRIPTION

      readahead() populates the page cache with data from a file so that subsequent reads from that file will not block
      on disk I/O.  The fd argument is a file descriptor identifying the file which is to be read.  The offset argument
      specifies  the  starting  point from which data is to be read and count specifies the number of bytes to be read.
      I/O is performed in whole pages, so that offset is effectively rounded down to a page boundary and bytes are read
      up  to  the next page boundary greater than or equal to (offset+count).  readahead() does not read beyond the end
      of the file.  readahead() blocks until the specified data has been read.  The current file  offset  of  the  open
      file referred to by fd is left unchanged.

RETURN VALUE

      On success, readahead() returns 0; on failure, -1 is returned, with errno set to indicate the cause of the error.

ERRORS

      EBADF  fd is not a valid file descriptor or is not open for reading.
 
      EINVAL fd does not refer to a file type to which readahead() can be applied.