How to make X11/Extension API changes?
krahn at niehs.nih.gov
Tue Sep 6 09:15:20 PDT 2005
How does one make API changes that need extended data structures without
backwards compatibility problems? X was designed carefully enough that
this is seldom an issue.
MS-Windows likes to have callers initialized a struct with a
sizeof(struct) value, so structures can be extended, with additional
data returned according to the structure size. It also uses -Ex suffixes
for a one-time function prototype change.
X solves this partly by protocol versioning. But, what is the right way
to make structure/function changes at the API level?
Can XListInputDevices contain a pointer to an extended XValuatorInfo
structure, as long as the initial structure members match the current
XInput Device Controls are 'almost' extensible as-is, if controlType
were changed from int to Atom, which are binary compatible. What is the
best way to update a function like this without something weird like
adding an -Ex suffix?
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