The '''Tcl IO [tcl core subsystems%|%subsystem]''' provides various [Tcl C API]
functions and is is used by `[chan]` and `[socket]`.


** See Also **

   [Tcl IO Drivers] aka ''The Tcl I/O system as seen by a driver (channel type)'', by [AKU] :   Describes the I/O system used in the Tcl core as it is seen from a driver implementing a channel type.

   [The interaction between the I/O subsystem and the notifier]:   A description of the connections between I/O and Notifier components relevant to the generation and handling of file events.

   [Channel Implementations]:   

   [https://core.tcl.tk/tcl/artifact?filename=generic/tclIOGT.c&ci=trunk%|%TclIOGT.c]:   Implements a generic transformation exposing the underlying API at the script level.  Used by [https://core.tcl.tk/tcl/artifact?udc=1&ln=591-594&name=12f6bb45f936ff07%|%TestChannelCmd] in the Tcl test suite.  Together these pieces are a good example for constructing stacked channels at the [C] level.



<<categories>> Channel