RE: SWIG: std::string returned as reference - solution

I've created the following typemaps to support argument passing by
reference.

Unfortunately SWIG does not like function templates such as:

template< class T>
%typemap(in) T& ($basetype temp) {

        --code
}

So I have to implement this separately.

/**
 * IN STRING TYPE MAP
 * 
 */
%typemap(in) std::string& ($basetype string_temp) {
        if (!SvPOK($input)) {
                croak("Argument $argnum is not a string");
        }
    $1 = &string_temp;
}

/**
 * IN STRING ARG OUT TYPE MAP
 * 
 */
%typemap(argout) std::string& OUTPUT {
   
   sv_setpv( $input, (*$1).c_str() );
}

/**
 * IN INT TYPE MAP
 * 
 */
%typemap(in) unsigned short& ($basetype int_temp), 
                         short& ($basetype int_temp), 
                         unsigned int& ($basetype int_temp),    
                         int& ($basetype int_temp),
                         unsigned char& ($basetype int_temp) {
        
        if (!SvIOK($input)) {
                croak("Argument $argnum is not an integer");
        }
    $1 = &int_temp;
}

/**
 * IN Int ARG OUT TYPE MAP
 * 
 */
%typemap(argout) unsigned short& OUTPUT, 
                                 short& OUTPUT, 
                                 unsigned int& OUTPUT, 
                                 int& OUTPUT, 
                                 unsigned char& OUTPUT {
 
   sv_setiv( $input, (*$1) );
}

/**
 * APPPLY THIS TYPEMAP TO ALL REF PARAMS.
 */
%apply std::string& OUTPUT { std::string& };
%apply int& OUTPUT { int& };
%apply int& OUTPUT { unsigned short& };
%apply int& OUTPUT { short& };
%apply unsigned short& OUTPUT { unsigned short& };
%apply unsigned char& OUTPUT { unsigned char& };



Thanks,
-sanjay








-----Original Message-----
From: David Beazley [mailto:beazley@xxxxxxxxxxxxxxx] 
Sent: Wednesday, November 19, 2003 1:48 PM
To: Nair, Sanjay S
Cc: David Beazley; swig@xxxxxxxxxxxxxxx
Subject: RE: [Swig] SWIG: std::string returned as reference - solution

Nair, Sanjay S writes:
 > > This is different than most OUTPUT typemaps which do not modify
their
 > > arguments.  Use std::string &REFERENCE if you're going to do that
(to
 > > be consistent with other typemaps that behave in the same way).
 > 
 > What happens if you have multiple out params?
 > 
 > 

Well, that's an entirely different problem. 
 >  > 
 >  > %typemap(in) std::string*, std::string& ($basetype string_temp) {
 >  >   if (!SvPOK($input)) {
 >  >           croak("Argument $argnum is not a string");
 >  >   }
 >  >   $1 = &string_temp;
 >  >   argvi++;
 >  > }
 >  > 

I just noticed this, but why are you incrementing argvi++ in an "in"
typemap?  That's related to output, not input.

-- Dave
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