Calling 'c' function from PostGreSQL

Is it possible to call a language 'C'  function from a PL/pgSQL function. I have the following code:

 

// file myfunc.c

#include "postgres.h"

 

text* myfunc();

 

text* myfunc()
{
 text* ch;
 *ch = '1,2';
 return ch;
}

 

// C file ends here

 

create function myfunc as

'myfunc.so' langauge 'c';

 

create function test() returns text as '

declare
    at text;
begin
    at := myfunc();
    return at;
end;
' language 'plpgsql';

 

The above when executed gives pqReadData()-- backend closed the channel unexpectedly.