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From Greg Stein <>
Subject RE: binary backwards compatability.
Date Thu, 30 Mar 2000 01:30:05 GMT
On Wed, 29 Mar 2000, Dean Gaudet wrote:
> ... lots o' stuff ...

I gotta go with Dean, partially. Trying to maintain backwards compat is
awfully difficult, and given the experiences with Linux, it is
"acceptable" in an Open Source environment.

However: I like Ryan's suggestion for an *optional* version checking
function. If the function is not provided, then we use the current check.
If the function does it exist, then it will be called IFF the module's
major version is >= Apache's major version. The module can make allowances
for running against *old* Apache servers (NOT newer ones!).

Consider the M_INVALID change: I could write a module today that
understands the current and old values, and compensates accordingly.
Likewise, I might have two code paths for dealing with different semantics
of some API functions. Maybe my module dynamically looks up exported
API functions, allowing dynamic use of certain functionality.

I agree with Dean that a module should not be allowed to run *if* Apache
is newer than the module (as defined by MAJOR); there is no way the module
could know if its use of Apache has changed or not.
[ I think that Dean was only looking in one direction of time... ]


Greg Stein,

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