Intel XENIX 286 Programmers Guide (86) - Tenox.tc

XENIX Programming SCCS: Source Code Control System
Using Identification Keywords
sees provides several special symbols, called identification keywords, that can be used
in the text of a program or document to represent predefined values. Keywords
represent values ranging from the creation date and time of a given file to the name of
the module containing the keyword. When a user retrieves the file for reading, sees
automatically replaces each keyword it finds in a given version of a file with the
keyword's value.
This section explains how keywords are treated by the various SCCS commands and how
you may use the keywords in your own files. Only a few keywords are described in this
section. For a complete list of the keywords, see get in Appendix B, "Programming
Commands."
Inserting a Keyword into a File
You may insert a keyword into any text file. A keyword is simply an uppercase letter
enclosed in percent signs {%}. For example, 96196 is the keyword representing the SID of
the current version, and 96H96 is the keyword representing the current date.
When a file is retrieved for reading using the get command, the keywords are replaced
by their current values. For example, if the 96M96, 96196, and 96H96 keywords are used in
place of the module name, the SID, and the current date in the program statement
char header( 100) = {" %M% %1% %H% "};
then these keywords are expanded in the retrieved version of the program
char header( 1 00) = {" MODNAME 2.3 07107177 "};
The get command does not replace keywords when retrieving a version for editing. SCCS
assumes that you wish to keep the keywords (and not their values) when you save the
new version of the file.
To indicate that a file has no keywords, the get, delta, and admin commands display the
message
No id keywords (cm7)
This message is normally treated as a warning, letting you know that no keywords are
present. However, you may change the operation of the system to make this a fatal
error as explained later in this chapter.
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