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foreign routine. It understands messages for calling the foreign routine and has associated with it a foreignCode
object. The foreignFct and foreignCode objects cooperate with the linker, to ensure that object files are
transparently loaded when necessary and that fctProxies depending on an object file are killed when the object
file is unloaded, etc.
The foreignCodeDB object ensures that foreignCode objects are unique, given a path. It also allows for specifying initializers and finalizers on foreignCode objects. An initializer is a foreign routine that is called whenever
the object file is loaded. Initializers take no arguments and do not return values. Typically, they initialize global data
structures. Finalizers are called when an object file is unloaded. When debugging foreign routines, foreignCodeDB
printStatus outputs a useful overview.
Normal use of a foreign routine simply involves cloning a foreignFct object to represent the foreign routine. When
cloning it, the name of the function and the path of the object file is specified. It is then not necessary to worry about
proxy, fctProxy and linker objects, etc. In fact, it is recommended not to send messages directly to these
objects, since this may break the higher level invariants that foreignFct objects rely on.
Relevant oddballs:
linker
sunLinker
foreignCodeDB
dynamic linker for current platform
dynamic linker implementation for SunOS/Solaris
registry for foreignCode objects
Modules: foreign
3.11 I/O and Unix
oddball
unix
clonable
proxy
unixFile (mixes in traits unixFile currentOsVariant)
The oddball object unix provides access to selected Unix system calls.
The most common calls are
the file operations: creat(), open(), close(), read(), write(), lseek() and unlink().
tcpConnectToHost:Port:IfFail: opens a TCP connection. The select() call and the indirect system
call are also supported (taking a variable number of integer, float or byte vector arguments, the latter being passed
as C pointers). unixFile provides a higher level interface to the Unix file operations. The oddball object tty
implements terminal control facilities such as cursor positioning and highlighting.
Relevant oddballs:
stdin, stdout, stderr
tty
standard Unix streams
console terminal capabilities
Modules: unix, stdin, tty, ttySupport, termcap
3.12 Other Objects
Here are some interesting oddball objects not discussed elsewhere:
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Chapter 3. The Self World