This task has been clarified. Its programming examples are in need of review to ensure that they still fit the requirements of the task.
This task is inverse to the task Call foreign language function. Consider the following C program:

#include <stdio.h>
 
extern int Query (char * Data, size_t * Length);
 
int main (int argc, char * argv [])
{
   char     Buffer [1024];
   size_t   Size = sizeof (Buffer);
 
   if (0 == Query (Buffer, &Size))
   {
      printf ("failed to call Query\n");
   }
   else
   {
      char * Ptr = Buffer;
      while (Size-- > 0) putchar (*Ptr++);
      putchar ('\n');
   }
}
Implement the missing Query function in your language, and let this C program call it. The function should place the string Here am I into the buffer which is passed to it as the parameter Data. The buffer size in bytes is passed as the parameter Length. When there is no room in the buffer, Query shall return 0. Otherwise it overwrites the beginning of Buffer, sets the number of overwritten bytes into Length and returns 1.

// query.c
// export zklRoot=/home/ZKL
// clang query.c -I $zklRoot/VM -L $zklRoot/Lib -lzkl -pthread -lncurses -o query
// LD_LIBRARY_PATH=$zklRoot/Lib ./query
 
#include <stdio.h>
#include <string.h>
 
#include "zklObject.h"
#include "zklImports.h"
#include "zklClass.h"
#include "zklFcn.h"
#include "zklString.h"
 
int query(char *buf, size_t *sz)
{
   Instance *r;
   pVM       vm;
   MLIST(mlist,10);
 
   // Bad practice: not protecting things from the garbage collector
 
   // build the call parameters: ("query.zkl",False,False,True)
   mlistBuild(mlist,stringCreate("query.zkl",I_OWNED,NoVM),
              BoolFalse,BoolFalse,BoolTrue,ZNIL);
   // Import is in the Vault, a store of useful stuff
   // We want to call TheVault.Import.import("query.zkl",False,False,True)
   //    which will load/compile/run query.zkl
   r = fcnRunith("Import","import",(Instance *)mlist,NoVM);
   // query.zkl is a class with a var that has the query result
   r = classFindVar(r,"query",0,NoVM);  // -->the var contents
   strcpy(buf,stringText(r));     // decode the string into a char *
   *sz = strlen(buf);   // screw overflow checking
   return 1;
}
 
int main(int argc, char* argv[])
{
   char   buf[100];
   size_t sz = sizeof(buf);
 
   zklConstruct(argc,argv);	// initialize the zkl shared library
   query(buf,&sz);
   printf("Query() --> \"%s\"\n",buf);
 
   return 0;
}