FUNCTION c_arcseek (arcdesc, line)
long *arcdesc; long line;
The archive file descriptor returned by c_arcopnrd() or c_arcopnwrt().
Number of the next line that should be returned by c_arcread() or the next line that should be written by c_arcwrite(). When used with c_arcread(), this number must be relative to the window that the image was opened with and it cannot lie outside the window. If the image is being processed in a "North-up" order, this line number is relative to the "North-up" window, otherwise, it is relative to the order the lines were acquired.
Seek to the specified line number in the AVHRR archive image. If this function returns a successful status, the next call to c_arcread() or c_arcwrite() will return or write the specified line. Successive calls to these functions will return or write line+1, line+2, and so on.
The AVHRR archive I/O routines use an internal buffer to read and write a specified number of lines at a time. This reduces the number of disk accesses that are required to process an AVHRR image. If seeking is done in such a way that the buffer must be refilled for each line that is accessed, processing speed will degrade.
Seeking to a line that lies before the first line in the internal buffer is not allowed when reading an image from an AVHRR archive tape.
c_arcseek() returns
E_SUCC (0) --> Successful completion. E_FAIL (-1) --> Operation failed.