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[comment {-*- mode: tcl ; fill-column: 90 -*-}]
[list_begin enumerated]
[enum] Reread the example of the main section. Note specifically the line [example {
int {level ZSTD_CLEVEL_DEFAULT}
}]
[enum] This line demonstrates that [cmd critcl::cproc] arguments allowed to have default
values, in the same vein as [cmd proc] arguments, and using the same syntax.
[enum] [emph Attention] Default values have to be legal C rvalues and match the C type of
the argument.
[para] They are literally pasted into the generated C code.
[para] They bypass any argument validation done in the generated translation layer. This
means that it is possible to use a value an invoker of the command cannot use from Tcl.
[enum] This kind of in-band signaling of a default versus a regular argument is however
not necessary.
[para] Look at [example {
critcl::cproc default_or_not {int {x 0}} void {
if !has_x {
printf("called with default\n");
return
}
printf("called with %d\n", x);
}
}]
[para] Any argument [arg x] with a default causes [vset critcl] to create a hidden
argument [arg has_x], of type int (boolean).
This argument is set to [const 1] when [arg x] was filled from defaults, and [const 0]
else.
[list_end]
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