I don't know the details, but it should be something like this:
  1. synthesize an OP o for vec
  2. set up the runtime environment: push the arguments on the stack, save PL_op and make it point to the synthesized OP o, set any other interpreter globals, stacks, etc.
  3. call CALLRUNOPS
  4. retrieve the result from o->op_targ
  5. clean up
For and example, look at Perl_fold_constants from op.c from the perl source. Try running it inside a C debugger with a simple fold-able expression as print(1+2).

The C function Perl_op_dump can be used to dump an OP tree once it has been properly build (otherwise it will crash).

In reply to Re^3: Using vec() from XS by salva
in thread Using vec() from XS by BrowserUk

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