Keywords: gildas-prog

Next: Image Slot Handling Up: Task Programming Manual Previous: GIO API Contents Index

# Obsolete Fortran-77 access routines

Caution: These routines are obsolete. Documentation only provided for historical reasons. It may disappear at some point or be moved to another document.
In Fortran-77, neither virtual memory handling, nor data structures, are part of the language. We had written a number of routines to access images. These routines are more complex than the new Fortran-90 method of access, and are provided here just for completeness.

To read a file requires six basic steps:

- allocation of an Image Slot using `GDF_GEIS`.
- connection of an image to the slot using `GDF_REIS` or `GDF_WRIS`.
- reading the header using `GDF_RHSEC`
- connection of a Memory Slot to the image (or a subset of it) using `GDF_GEMS`
- once the Memory Slot is no longer needed, disconnection using `GDF_FRMS`
- once the image slot is no longer required, disconnection using `GDF_FRIS`

Creation of a new file is slightly different:

- allocation of an Image Slot using `GDF_GEIS`
- preparatin of the header using e.g. `GDF_WHSEC`
- creation of the image to the slot using `GDF_CRIS`. The header is written at this stage.
- connection to the image (or a subset of it) using `GDF_GEMS`
- once the Memory Slot is no longer needed, disconnection using `GDF_FRMS`. This is the step which actually does the writing.
- once the image slot is no longer required, disconnection using `GDF_FRIS`

Subsections

- Image Slot Handling
- Image Connection
- Memory Connection

Next: Image Slot Handling Up: Task Programming Manual Previous: GIO API Contents Index