DESIGN OF THE MPS LIBRARY VERSION MECHANISM
                       design.mps.version-library
                             incomplete doc
                             drj 1998-08-19

INTRODUCTION

.intro: This describes the design of a mechanism to be used to determine the 
version (that is, product, version, and release) of an MPS library.


READERSHIP

.readership: Any MPS developer.


SOURCE

.source: Various requirements demand such a mechanism.  See 
request.epcore.160021: There is no way to tell which version and release of the 
MM one is using.


OVERVIEW

.overview: See design.mps.version for discussion and design of versions of 
other aspects of the software.  This document concentrates on a design for 
determining which version of the library one has linked with.  There are two 
aspects to the design, allowing humans to determine the version of an MPS 
library, and allowing programs to determine the version of an MPS library.  
Only the former is currently designed (a method for humans to determine which 
version of an MPS library is being used).

.overview.impl: The overall design is to have a distinctive string compiled 
into the library binary.  Various programs and tools will be able to extract 
the string and display it.  The string will identify the version of the MPS 
begin used.


ARCHITECTURE

.arch.structure: The design consists of 3 components:

.arch.string: A string embedded into any delivered library binaries (which will 
encode the necessary information).

.arch.proc: A process by which the string is modified appropriately whenever 
releases are made.

.arch.tool: A tool and its documentation (it is expected that standard tools 
can be used).  The tool will be used to extract the version string from a 
delivered library or an executable linked with the library.

.arch.not-here: Only the string component (:arch.string) is directly described 
here.  The other components are described elsewhere.  (where?)

The string will contain information to identify the following items:
.arch.string.platform: the platform being used.
.arch.string.product: the name of the product.
.arch.string.variety: the variety of the product.
.arch.string.version: the version and release of the product.


IMPLEMENTATION

.impl.file: The string itself is a declared C object in the file version.c 
(impl.c.version).  It consists of a concatenation of various strings which are 
defined in other modules.

.impl.variety: The string containing the name of the variety is the expansion 
of the macro MPS_VARIETY_STRING defined by config.h (impl.h.config).

.impl.product: The string containing the name of the product is the expansion 
of the macro MPS_PROD_STRING defined by config.h (impl.h.config).

.impl.platform: The string containing the name of the platform is the expansion 
of the macro MPS_PF_STRING defined by mpstd.h (impl.h.mpstd).

.impl.date: The string contains the date and time of compilation by using the 
__DATE__ and __TIME__ macros defined by ISO C (ISO C clause 6.8.8).

.impl.version: The string contains the version and release of the product.  
This is by the expansion of the macro MPS_RELEASE which is defined in this 
module (version.c).

.impl.usage: To make a release, the MPS_RELEASE macro (see 
impl.c.version.release) is edited to contain the release name (e.g., 
"release.epcore.brisling"), and then changed back immediately after the release 
checkpoint is made.