.TH IOCallback 3I "21 December 1990" "InterViews" "InterViews Reference Manual"
.SH NAME
IOCallback \- generic callback class for readers, writers, or I/O exception handlers
.SH SYNOPSIS
.B #include <Dispatch/iocallback.h>
.SH DESCRIPTION
For convenience, the macros defined in iocallback.h allow the user to
define an iohandler which does nothing more than call an arbitrary
object's member function.  The actual code to read data from a file
descriptor, write data to a file descriptor, handle an I/O exception
on a file descriptor, or handle a timer's expiration can reside in any
arbitrary class rather than in the iohandler.
.SH MACROS
.TP
.B "declareIOCallback(T)"
Declare an iocallback type for the given class type T.
.TP
.B "implementIOCallback(T)"
Emit code at this point to implement the iocallback's member
functions.
.TP
.B "IOCallback(T)* instance = new IOCallback(T)(...)"
Define an instance of the iocallback type for the given class type T.
.SH CONSTRUCTORS
.TP
.B "typedef int T::IOReady(T)(int fd)"
.ns
.TP
.B "typedef void T::IOTimer(T)(long sec, long usec)"
.TP
.B "IOCallback(T)(T*, IOReady(T)* in, IOReady(T)* out = nil, IOReady(T)* ex = nil)"
.ns
.TP
.B "IOCallback(T)(T*, IOTimer(T)*, IOReady(T)* in = nil, IOReady(T)* out = nil, IOReady(T)* ex = nil)"
Construct an instance of the iocallback type that will call the given
member functions of the given class type T's instance.  Note that you
do not have to use the IOReady(T) or IOTimer(T) macros; rather, you
only have to pass the address of a T member function, such as
&T::inputReady.
.SH SEE ALSO
Dispatcher(3I), IOHandler(3I)