Oo_Installsystemhook - Texas Instruments TI-89 Developer's Manual

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OO_InstallSystemHook

Declaration: BOOL OO_InstallSystemHook (pFrame hookFrame , pFrame * retFrame )
Category(ies): Apps, Operating System
Description: This routine refines the system object frame, overriding or adding
attributes, by hooking a new frame at the head of the system object parent
hierarchy.
Many system attributes are hard-coded in Flash memory and cannot be
changed — the built-in table of strings, for example. A language localizer
gains the effect of changing the system string table by hooking a new
frame containing the equivalent strings of a different language ahead of the
system object frame.
Multiple hooks can be installed over the system frame, the latest-installed
having highest precedence during attribute look-up. Attribute search begins
the with latest-installed hook frame and proceeds through each hook all the
way back to the system object frame until the attribute is found.
Hooks can be uninstalled in any order. See OO_UninstallSystemHook to
learn how to uninstall system hooks.
Inputs: hookFrame — Pointer to hook frame.
retFrame
Outputs: Returns TRUE if hook was installed. Returns FALSE if memory for RAM
link frame could not be allocated.
None
Assumptions:
Side Effects: May cause heap compression.
Availability: On AMS 2.00 and higher.
TI-89 / TI-92 Plus
Differences: None
See Also: OO_UninstallSystemHook
TI-89 / TI-92 Plus Developer Guide
Appendix A: System Routines — Apps
— Returned pointer to RAM link frame. Keep this value
around and pass it to OO_UninstallSystemHook when
you want to unhook the frame.
(continued)
Not for Distribution Beta Version January 26, 2001