I have embedded a Perl interpreter in a C program and loaded the following Perl code into it. 

package xmlutil;
use XML::Simple;
#use strict; # I need symbolic dereferencing.

my $xmlFile = "./galaxy.xml";
my $config = XMLin($xmlFile);

sub get_ival {
    $parm_str = $_[0];

    # reference the parameter directly. Prints Jane's number
    print "ref1 = ", $config->{jane}->{tel_no}, "\n";

    # attempt to use symbolic dereference. Yields nothing!
    print "ref2 = ", $$parm_str, "\n";

    # construct the same symbolic reference locally
    # just to make sure. Still yields nothing!
    $parm_str = "\$" . "config->{jane}->{tel_no}, "\n";
    print "ref3 = ", $$parm_str, "\n";
}

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My intension is to use the XML::Simple interface from the C code to extract data from the XML. I am currently using the following C code to call the Perl subroutine. 

void get_ival( int *int_p, char *parm_str_p )
{
    char cmd_str[255];
    STRLEN na;
    SV *val;
    dSP;

    ENTER;
    SAVETMPS;
    PUSHMARK(SP);
    XPUSHs( sv_2mortal( newSVpv( parm_str_p, 0 ) ) );
    PUTBACK;

    call_pv( "xmlutil::get_ival", G_DISCARD );

    FREETMPS;
    LEAVE;
}

[download]

Can anyone shine a light on how I work arround this problem?

Thanks for your help Wise Ones! :)

Phil

Please note that the square brace characters went funny when I submitted this text. They are there in a couple of places and have turned into links(?) :)

Edit ar0n -- replaced pre with code tags

In reply to Problem with symbolic deferencing into XML::Simple's internal representation of an XML file. by Anonymous Monk

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