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critcl::iassoc(n) C Runtime In Tcl (CriTcl) critcl::iassoc(n)
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NAME
critcl::iassoc - CriTcl Utilities: Tcl Interp Associations
SYNOPSIS
package require Tcl 8.4
package require critcl ?3.1?
package require critcl::iassoc ?1?
::critcl::iassoc::def name arguments struct constructor destructor
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DESCRIPTION
Welcome to the C Runtime In Tcl, CriTcl for short, a system to build C
extension packages for Tcl on the fly, from C code embedded within Tcl
scripts, for all who wish to make their code go faster.
This document is the reference manpage for the critcl::iassoc package.
This package provides convenience commands for advanced functionality
built on top of the critcl core.
With it a user wishing to associate some data with a Tcl interpreter
via Tcl's Tcl_(Get|Set)AssocData() APIs can now concentrate on the data
itself, while all the necessary boilerplate around it is managed by
this package.
Its intended audience are mainly developers wishing to write Tcl
packages with embedded C code.
This package resides in the Core Package Layer of CriTcl.
+----------------+
|Applications |
| critcl |
| critcl::app |
+----------------+
*================*
|Core Packages |
| critcl |
| critcl::util |
*================*
+----------------+
|Support Packages|
| stubs::* |
| md5, platform |
| ... |
+----------------+
API
::critcl::iassoc::def name arguments struct constructor destructor
This command defines a C function with the given name which
provides access to a structure associated with a Tcl
interpreter.
The C code code fragment struct defines the elements of said
structure, whereas the fragments constructor and destructor are
C code blocks executed to initialize and release any dynamically
allocated parts of this structure, when needed. Note that the
structure itself is managed by the system.
The new function takes a Tcl_Interp* pointer refering to the
interpreter whose structure we wish to obtain as the first
argument, plus the specified arguments and returns a pointer to
the associated structure, of type "name_data" (see below).
The arguments are a dictionary-like list of C types and
identifiers specifying additional arguments for the accessor
function, and, indirectly, the constructor C code block. This is
useful for the supplication of initialization values, or the
return of more complex error information in case of a
construction failure.
The C types associated with the structure are derived from name,
with "name_data__" the type of the structure itself, and
"name_data" representing a pointer to the structure. The C code
blocks can rely on the following C environments:
constructor
data Pointer to the structure (type: name_data) to
initialize.
interp Pointer to the Tcl interpreter (type: Tcl_Interp*)
the new structure will be associated with.
error A C code label the constructor can jump to should
it have to signal a construction failure. It is
the responsibility of the constructor to release
any fields already initialized before jumping to
this label.
... The names of the constructor arguments specified
with arguments.
destructor
data Pointer to the structure being released.
interp Pointer to the Tcl interpreter the structure
belonged to.
EXAMPLE
The example shown below is the specification of a simple interpreter-
associated counter. The full example, with meta data and other
incidentals, can be found in the directory "examples/queue" of the
critcl source distribution/repository.
package require Tcl 8.4
package require critcl 3.1
critcl::buildrequirement {
package require critcl::iassoc
}
critcl::iassoc::def icounter {} {
int counter; /* The counter variable */
} {
data->counter = 0;
} {
/* Nothing to release */
}
critcl::ccode {
... function (...)
{
/* Access to the data ... */
icounter_data D = icounter (interp /* ... any declared arguments, here, none */);
... D->counter ...
}
}
# or, of course, 'cproc's, 'ccommand's etc.
package provide icounter 1
AUTHORS
Andreas Kupries
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such at
https://github.com/andreas-kupries/critcl. Please also report any
ideas for enhancements you may have for either package and/or
documentation.
KEYWORDS
C code, Embedded C Code, Tcl Interp Association, code generator,
compile & run, compiler, dynamic code generation, dynamic compilation,
generate package, linker, on demand compilation, on-the-fly
compilation, singleton
CATEGORY
Glueing/Embedded C code
COPYRIGHT
Copyright (c) 2011-2015 Andreas Kupries
doc 1 critcl::iassoc(n)