Re: Dynamically loaded functions -- Using C++ associative arrays

[E. Joshua Rigler]

This is NOT an answer to my original question, but rather a
demonstration of how an almost identical piece of code, except designed
as a standalone main() function, DOES work.  Any ideas as to why trying
to do this in an Octave dynamically linked function would cause the
crash I mentioned previously?  I am using RH-7.1's latest version of
G++.

Thanks in advance for any help.

-EJR


////////
//
// Test function for simple associative array
//
// test_map2.cc
//
////////

#include <iostream>
#include <string>
#include <map>

int main(int argc, char *argv[])
{
  
  int i;

  std::map<std::string,int> m1;
  std::map<std::string,int>::iterator p;
  
  m1["test1"] = 1;
  m1["test2"] = 2;
  m1["test10"] = 10;

  for (i=1; i<argc; i++)
    {

      // Is there a matching key in our associative array
      p = m1.find( argv[i] );
      if (p != m1.end () )
        {
          // If there's a match, print its value
          cout << m1[argv[i]] << "\n";
        }

    }

}



////////
//
// Test output from test_map2
//
////////

<~/src/octave/oct> ./test_map2 test1 test test10 test1 test1 test2 lala
1
10
1
1
2
<~/src/octave/oct> 




"E. Joshua Rigler" wrote:
> 
> First, please excuse my lack of C++ expertise, this is all fairly new to
> me.
> 
> I am attempting to implement an associative array using the std::map<>
> class.  It took me a while, but I think I finally figured it out, and
> even got a simple test function to compile with mkoctfile.  However, I
> get an undefined symbol error when I try to use the function in octave,
> and octave crashes.
> 
> I've attached my short test program, along with the error I get when I
> attempt to call it from octave.  Do I need to link to a special library
> when I compile?  What's going on here?
> 
> Thanks,
> 
> -EJR
> 
> ////////
> //
> // Test function for simple associative array
> //
> // test_map.cc
> //
> ////////
> 
> #include <octave/oct.h>
> #include <map>
> 
> DEFUN_DLD (test_map, args, nargout,"...")
> {
> 
>   octave_value retval;
> 
>   static std::map<std::string,int> m1;
>   static std::map<std::string,int>::iterator p;
> 
>   m1["test1"] = 1;
>   m1["test2"] = 2;
>   m1["test10"] = 10;
> 
>   // Is there a matching key in our associative array?
>   p = m1.find(args(0).string_value () );
>   if (p != m1.end() )
>     {
>       // If there's a match, return its value
>       cout << m1[args(0).string_value ()];
>       retval = 1.0;
>     }
> 
>   return retval;
> 
> }
> 
> ////////
> //
> // Test output from test_map.oct
> //
> ////////
> 
> 1092 <~/src/octave/oct> octave
> GNU Octave, version 2.1.33 (i686-pc-linux-gnu).
> Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 John W. Eaton.
> This is free software with ABSOLUTELY NO WARRANTY.
> For details, type `warranty'.
> 
> octave:1> test_map ("test1")
> octave: error while loading shared libraries:
> /home/jrigler/src/octave/oct/test_map.oct: undefined symbol:
> lower_bound__t8_Rb_tree5Zt12basic_string3ZcZt18string_char_traits1ZcZt24__default_alloc_template2b1i0Zt4pair2ZCt12basic_string3ZcZt18string_char_traits1ZcZt24__default_alloc_template2b1i0ZiZt10_Select1st1Zt4pair2ZCt12basic_string3ZcZt18string_char_traits1ZcZt24__default_alloc_template2b1i0ZiZt4less1Zt12basic_string3ZcZt18string_char_traits1ZcZt24__default_alloc_template2b1i0Zt9allocator1ZiRCt12basic_string3ZcZt18string_char_traits1ZcZt24__default_alloc_template2b1i0



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