Status and Text Reference Coding

Requirements

Primary Requirements – phase I

• The results of the project must be usable in 'C' language or 'C' language derivative programs.
• The status information must indicate whether or not the current result is usable.  In particular the standard macro EXIT_SUCCESS must indicate a usable result and the standard macro EXIT_FAILURE must indicate an unusable result.
• The status information should also indicate whether or not the current operation sequence can continue.  In particular the standard macro EOF must indicate no usable result and that normal operations can not continue without intervention.
• Any additional space in the status value should be used to provide details of what the context of the generated status code was.  This might include which library or program generated the status and a status category.
• The library or program identifiers should probably be grouped to indicate the people or company responsible for maintaining the library or program.

Secondary Requirements

• The implementation should make it easier to quickly understand the intent of the code.  For example, a macro called isGood(status) or isBad(status) reads faster than a mask and compare expression.
• Given the ability to associate a particular text string with a particular status code, it is probably desirable to allow access to translations of other text strings using this facility.

It would be nice if...

The text storage scheme could make it easier to translate the text from one language to another.  For example, different languages have different standard word orders for different kinds of sentences.  If a meta-language description or grammatical analysis of the text to be translation was available, it could simplify the translation process.  Similarly, the identification of particular words or phrases that appear in many different messages could be identified, translated once and used consistently in all messages.

One use of return status values is to return a count of some sort back to the caller along with the usual indicators.  (There was a VMS internal bug where the caller expected a status_t equivalent while the called routine actually returned a count.  The problem delayed the acceptance of a significant set of security capabilities.)

Primary Requirements – phase II

Note that the information in this section is preliminary and subject to change when Phase I is complete.

• A function or method should exist that maps the status code to displayable text.
• It should be possible to change the status code to text mapping depending on the user's language or cultural preference.

References

Note that access to POSIX standards requires a free (as in beer) registration.

EXIT_SUCCESS

EXIT_FAILURE

Both EXIT_SUCCESS and EXIT_FAILURE are defined by POSIX.1 <stdlib.h>.

EOF

See POSIX.1 <stdio.h>.

Text lookup

VMS $PUTMSG system service.

[others TBS]

NOTE

The information on this page is preliminary and will not be maintained after initial development is complete.  For current information see the Programmer's Guide.

Work List:

• Add POSIX text lookup citations to the references.
• Is $PUTMSG the correct referent? $GETMSG?