Specifications

11
Additional Programming Utilities
In addition to the utilities already described in this manual, the OpenVMS
operating system also includes the following programming utilities that you can
use to develop application programs:
• Patch utility
• National Character Set (NCS) utility
This chapter briefly describes the features of these programming utilities and
references the appropriate manuals for more information about how to use them.
11.1 Patch Utility (VAX Only)
VAX
On VAX systems, the Patch utility (PATCH) allows you to make changes to an
image file in the form of patches. You can then run the new version of the image
without having to recompile (or reassemble) and relink the program. You can
enter PATCH commands interactively or use them in a command procedure to
execute interactively or in batch mode. You can use PATCH with any language
supported by the OpenVMS operating system as long as the image was generated
by the linker.
The input image can be a shareable image, a device driver image, or any other
executable image. Consider the following restrictions when you use PATCH:
• You can specify only universal symbols when patching a shareable image.
• You can use the default patch area to patch position-independent shareable
images.
• You must use a user-defined patch area to patch position-dependent images.
PATCH does not alter the input image. It creates a copy of the image, makes
changes to the copy, and leaves the original image unaltered.
With the PATCH commands, you can modify the image as follows:
• Add or delete instructions or data
• Replace instructions or data
• Allocate space for the patch area
• Create a command procedure of PATCH commands
• Assign an engineering change order-level to the changes
• View the contents of a particular location
• Display the modules in the image
• Apply the patch to the image
For more information about the Patch Utility, refer to the OpenVMS VAX Patch
Utility Manual.♦
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