1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
[comment {-*- mode: tcl ; fill-column: 90 -*-}]
[list_begin enumerated]
[enum] Reread the example in the [sectref {Errors And Messages} previous] section.
[enum] Note the type [type Tcl_Interp*] used for the first argument.
[enum] This type is special.
[enum] An argument of this type has to be the first argument of a function.
[enum] Using it tells [vset critcl] that the function needs access to the Tcl interpreter
calling it. It then arranges for that to happen in the generated C code.
[para] Using functions from Tcl's public C API taking an interpreter argument in the
function body is a situation where this is needed.
[enum] [emph {This special argument is not visible at the script level}].
[enum] [emph {This special argument is not an argument of the Tcl command for the function}].
[enum] In our example the [cmd sqrt] command is called with a single argument.
[enum] The name of the argument can be freely chosen. It is the type which is important
and triggers the special behaviour.
My prefered names are [var ip] and [var interp].
[list_end]
|
