FITS File Open and Close Subroutines:  

1

Open an existing FITS file with readonly or readwrite access

        FTOPEN(unit,filename,rwmode, > blocksize,status)

2

Open and initialize a new empty FITS file

        FTINIT(unit,filename,blocksize, > status)

3

Flush internal buffers of data to the output FITS file previously opened with ftopen or ftinit. The routine usually never needs to be called, but doing so will ensure that if the program subsequently aborts, then the FITS file will have at least been closed properly.

        FTFLUS(unit, > status)

4

Close a FITS file previously opened with ftopen or ftinit

        FTCLOS(unit, > status)

5

Close and DELETE a FITS file previously opened with ftopen or ftinit. This routine may be useful in cases where a FITS file is created, but an error occurs which prevents the complete file from being written.

        FTDELT(unit, > status)

6

Get the value of an unused I/O unit number which may then be used as input to FTOPEN or FTINIT. This routine searches for the first unused unit number in the range from with 99 down to 50. This routine just keeps an internal list of the allocated unit numbers and does not physically check that the Fortran unit is available (to be compatible with the SPP version of FITSIO). Thus users must not independently allocate any unit numbers in the range 50 - 99 if this routine is also to be used in the same program. This routine is provided for convenience only, and it is not required that the unit numbers used by FITSIO be allocated by this routine.

        FTGIOU( > iounit, status)

7

Free (deallocate) an I/O unit number which was previously allocated with FTGIOU. All previously allocated unit numbers may be deallocated at once by calling FTFIOU with iounit = -1.

        FTFIOU(iounit, > status)