C------------------------------------------------------------------------------
C       The following routines are part of the FITSIO library
C       and are specific to SUN SPARC, HP, IBM AIX, other similar computers.

C       On HP machines the +U77 compiler flag must be used when compiling
C       fitsio and any programs that call it, in order to link in the
C       BSF 3F library which contains the IDATE subroutine.

C       On IBM AIX machines, the -qcharlen=2880 compiler flag must be
C       used to support long character strings.
C------------------------------------------------------------------------------
C   This software was prepared by High Energy Astrophysic Science Archive
C   Research Center (HEASARC) at the NASA Goddard Space Flight Center. Users
C   shall not, without prior written permission of the U.S. Government,
C   establish a claim to statutory copyright.  The Government and others acting
C   on its behalf, shall have a royalty-free, non-exclusive, irrevocable,
C   worldwide license for Government purposes to publish, distribute,
C   translate, copy, exhibit, and perform such material. 
C--------------------------------------------------------------------------
        subroutine ftopnf(funit,fname,oldnew,rwmode,block,size,status)

C       low-level, machine-dependent routine to create or open a new file 
C
C       funit   i  Fortran I/O unit number
C       fname   c  name of file to be opened
C       oldnew  i  file status: 0 = open old/existing file; else open new file
C       rwmode  i  file access mode: 0 = readonly; else = read/write
C       block   i  FITS record blocking factor 
C       size    i  min size of file, in bytes
C       status  i  returned error status (0=ok)
C
C       written by Wm Pence, HEASARC/GSFC, December 1996

        integer funit,oldnew,rwmode,block,size,status
        character*(*) fname
        character*3 fstat

        if (oldnew .eq. 0)then
                fstat='OLD'
C               The blocking factor is irrelevant for files on a this machine, 
C               therefore, simply return the default block size.
                block=1
C               no easy way to determine the size of the file, 
C               so just set value to a huge number
                size=1000000000
        else
C               create a new file
                fstat='NEW'
                size = 0
        end if

C       Note that record size is given in units of bytes, not words.
        open(unit=funit,file=fname,status=fstat,err=900,
     &       recl=2880,form='UNFORMATTED',access='DIRECT')
        return

C       error opening file:
900     status=104 + oldnew
        end