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DUMMY_HANDLER |
Function (tigcc.a) |
A dummy interrupt handler doing nothing.
DUMMY_HANDLER is an interrupt handler of type INT_HANDLER
which consists only of 'rte'
. The purpose of this handler is
to redirect an interrupt vector to "nothing", in cases when disabling interrupts is not
possible. For example, you can not disable auto-int 1 in grayscale programs, because grayscale
support is based on it. Grayscale support installs its own auto-int 1 handler, which executes
the previously installed handler at the end. Suppose that you don't want it to call the default auto-int 1
handler, which trashes the status line by displaying keyboard status indicators. You can
redirect auto-int 1 to the dummy handler before enabling grayscale, so
after the grayscale interrupt, the dummy handler (i.e. nothing) will be called instead of the
default auto-int 1 handler:
INT_HANDLER save_int_1;
...
save_int_1 = GetIntVec (AUTO_INT_1);
SetIntVec (AUTO_INT_1, DUMMY_HANDLER); // redirect auto-int 1 to "nothing"
// enable grayscale
// do whatever you want in grayscale
// disable grayscale
SetIntVec (AUTO_INT_1, save_int_1);