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* Text: Operating System Dependencies                                         *
*                                                                             *
* File:                                                                       *
*    osdepend.txt                                                             *
*                                                                             *
* Description:                                                                *
*    This file briefly describes the places in the source files of the        *
*    GetImage program that are operating system dependent.  Currently, only   *
*    OpenVMS and UNIX are supported.                                          *
*                                                                             *
* History:                                                                    *
*    Created    : 25-JAN-94 by J. Doggett                                     *
*       for the Association of Universities for Research in Astronomy, Inc.   *
*          at the Space Telescope Science Institute,                          *
*       to facilitate the accessing of data from the CD-ROM set of the        *
*          Digitized Sky Survey.                                              *
*    Delivered  : 01-MAR-94 by J. Doggett                                     *
*       GetImage Version 1.0                                                  *
*                                                                             *
*    Updated    : 26-OCT-94 by J. Doggett                                     *
*       Updated for the ss_mount program.                                     *
*    Redelivered: 30-NOV-94 by J. Doggett                                     *
*       GetImage Version 1.1.                                                 *
*                                                                             *
* Copyright (c) 1994, Association of Universities for Research in Astronomy,  *
* Inc.  All Rights Reserved.                                                  *
* Produced under National Aeronautics and Space Administration grant          *
* NAG W-2166.                                                                 *
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config.h
        * Insures appropriate macros are defined to identify the operating
          environment.

filenams.c
        * The file included with the prototype for the library function
          "access" depends on the operating system.

        * The function Build_Full_File_Name calls the appropriate
          function (Build_Full_xxxx_File_Name, where xxxx identifies
          the operating system) to build a file name depending on the
          operating system.

getimage.c
        * The file included with the prototype for the library function
          "access" depends on the operating system.

        * The functions createUNIX_CDROMmountCommand, Get_Disc_Error_Action,
          and mountCDROM depend on the macro "USE_SSMOUNT" which, if
          defined, compiles in hooks for the ss_mount program which is used
          only with UNIX systems.

        * The function dismountCDROM calls the appropriate function
          (createxxxx_CDROMdismountCommand, where xxxx identifies the
          operating system) to build a dismount command depending on
          the operating system.

        * In the function Extract_Disc_List_HHH_Headers, if the header
          file to be created already exists, on OpenVMS systems a new
          version will be created, while on UNIX systems no new header

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* Operating System Dependencies page 2 *
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          file will be created to insure that the existing file is not
          overwritten.

        * In the function Extract_Disc_List_Images, if the image file to be
          created already exists, on OpenVMS systems a new version will be
          created, while on UNIX systems no new image will be created to
          insure that the existing file is not overwritten.

        * In the function Get_GetImage_Options, construction of the root
          directory for the image data depends on the operating system.

        * The function dismountCDROM calls the appropriate function
          (createxxxx_CDROMmountCommand, where xxxx identifies the
          operating system) to build a mount command depending on the
          operating system.

        * In the function Open_User_Output, if the output file to be
          created already exists, on OpenVMS systems a new version will be
          created, while on UNIX systems no new image will be created to
          insure that the existing file is not overwritten.

image.c
        * The file included with the prototype for the library function
          "access" depends on the operating system.

plate.c
        * The file included with the prototype for the library function
          "access" depends on the operating system.

        * In the function Plate_Directory_Exists, the name of the plate
          directory file depends on the operating system.

writeimg.c
        * The file included with the prototype for the library function
          "access" depends on the operating system.

        * In the function writefits, if the FITS file to be created
          already exists, on OpenVMS systems a new version will be created,
          while on UNIX systems no new FITS file will be created to insure
          that the existing file is not overwritten.

        * In the function writehhh, if the header file to be created
          already exists, on OpenVMS systems a new version will be created,
          while on UNIX systems no new header file will be created to
          insure that the existing file is not overwritten.

        * In the function writehhh, if the image file to be created
          already exists, on OpenVMS systems a new version will be created,
          while on UNIX systems no new image file will be created to
          insure that the existing file is not overwritten.

qfile.h
        * The image i/o required for OpenVMS is extremely system dependent.
          Most other systems may work with the UNIX code.


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* Operating System Dependencies page 3 *
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qread.c
        * The image i/o required for OpenVMS is extremely system dependent.
          Most other systems may work with the UNIX code.


ss_mount.c
        * This program was written exclusively for UNIX systems to handle
          the mounting of CD-ROM discs.  Because volume management is highly
          system dependent, there are many places throughout ss_mount.c
          which also are system dependent.  ss_mount is used only if the
          macro "USE_SSMOUNT" is defined in the source file "config.h".