Re^4: Passing integer pointer in XS? (XS << Perl)

in reply to Re^3: Passing integer pointer in XS? (XS << Perl)
in thread Passing integer pointer in XS?

What would be simpler than returning them in a hash? ...oh yeah, returning them in a list! Here ya go.

void
tdSensor()
   CODE:
   {
      char protocol[_MAX_PROTOCOL_LEN + 1];
      char model[_MAX_MODEL_LEN + 1];
      int  id;
      int  dataTypes;

      int rv = tdSensor(
         protocol, sizeof(protocol),
         model, sizeof(model),
         &id,
         &dataTypes
      );

      if (rv != TELLSTICK_SUCCESS) {
         XSRETURN(0);
      }

      EXTEND(SP, 4);
      ST(0) = sv_2mortal(newSVpv(protocol, 0)));
      ST(1) = sv_2mortal(newSVpv(model, 0));
      ST(2) = sv_2mortal(newIV(id));
      ST(3) = sv_2mortal(newIV(dataTypes));
      XSRETURN(4);
   }
[download]

Usage:

use feature qw( say );

while (my ($protocol, $model, $id, $dataTypes) = tdSensor()) {
   say join ', ',
      "protocol: $protocol",
      "model: $model",
      "sensorId: $id",
      "dataTypes: $dataTypes";
}
[download]

Untested.

Comment on Re^4: Passing integer pointer in XS? (XS << Perl) Select or Download Code

Replies are listed 'Best First'.
Re^5: Passing integer pointer in XS? (simpler) by tye (Sage) on Jul 18, 2016 at 22:14 UTC
If the first 4 arguments are for specifying ways to output 2 strings, then you can get simpler than that! int tdSensor( protocol, protocolLen, model, modelLen, id, dataTypes ) SV * protocol int protocolLen SV * model int modelLen int & id int & dataTypes CODE: { STRLEN n_a; (void) SvPV_force( protocol, n_a ); (void) SvPV_force( model, n_a ); SvGROW( protocol, protocolLen ); SvGROW( model, modelLen ); } RETVAL = tdSensor( SvPV(protocol), protocolLen, SvPV(model), modelLen, &id, &data +Types ); SvCUR_set( protocol, strlen(SvPV(protocol)) ); SvCUR_set( model, strlen(SvPV(model)) ); OUTPUT: RETVAL id dataTypes [download] But much simpler (and less likely to be buggy) than even that is: `int _tdSensor( protocol, protocolLen, model, modelLen, id, dataTypes ) char * protocol int protocolLen char * model int modelLen int & id int & dataTypes CODE: RETVAL = tdSensor( protocol, protocolLen, model, modelLen, &id, &d +ataTypes ); OUTPUT: RETVAL id dataTypes` [download] Plus `sub tdSensor { my( $protocolLen, $modelLen ) = @_; $protcolLen \|\|= 1024; $modelLen \|\|= 1024; my $protocol = '\0' x $protcolLen; my $model = '\0' x $modelLen; my $id = 0; my $dataTypes = 0; my $ret = _tdSensor( $protocol, $protocolLen, $model, $modelLen, $id, $dataTypes ); s/\0.*// for $protocol, $model; return( $ret, $protocol, $model, $id, $dataTypes ); }` [download] Which has the significant advantage of making it much easier to improve the interface without having to futz with the super finicky XS part of the code. - tye	[reply] [d/l] [select]
Re^6: Passing integer pointer in XS? (simpler) by ikegami (Patriarch) on Jul 19, 2016 at 07:02 UTC
But much simpler (and less likely to be buggy) than even that is: ~~Didn't I already demonstrate that it's quite buggy?~~ (Ok, so you're relying on the fact that manipulating the internal buffer of the scalar works in this situation even though you're not allowed to do it. As far as I'm concerned, you can't call simple something that relies on this level of knowledge of internals.) If the first 4 arguments are for specifying ways to output 2 strings, then you can get simpler than that! Really? Cause I would need to perform some testing to verify that it's correct. All that magic is far far more complicated than just returning the values.	[reply]
Re^7: Passing integer pointer in XS? (simpler) by Anonymous Monk on Jul 19, 2016 at 12:19 UTC
Check `PP(pp_sysread)`, it does pretty much the same. (Utf8 blah-blah is probably not relevant here.)	[reply] [d/l]

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