use ExtUtils::Typemaps; ... my $output = $typemap->get_output_map('T_NV'); my $code = $output->code(); $output->code("...");
In a nutshell, this will check whether the output code involves calling "sv_setiv", "sv_setuv", "sv_setnv", "sv_setpv" or "sv_setpvn" to set the special $arg placeholder to a new value AT THE END OF THE OUTPUT CODE. If that is the case, the code is eligible for using the "TARG"-related macros to optimize this. Thus the name of the method: "targetable".
If this optimization is applicable, "ExtUtils::ParseXS" will emit a "dXSTARG;" definition at the start of the generated XSUB code, and type (see below) dependent code to set "TARG" and push it on the stack at the end of the generated XSUB code.
If the optimization can not be applied, this returns undef. If it can be applied, this method returns a hash reference containing the following information:
type: Any of the characters i, u, n, p with_size: Bool indicating whether this is the sv_setpvn variant what: The code that actually evaluates to the output scalar what_size: If "with_size", this has the string length (as code, not constant, including leading comma)
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