Do I change the value of a defglobal in a correct way?

Question

I'm writing an app which should at some point get the value of a defglobal variable and change it. For this I do the following:

    DATA_OBJECT cur_time_q;
    if (!EnvGetDefglobalValue(CLIEnvironment, cur_timeq_kw, &cur_time_q)) return CUR_TIME_GLBVAR_MISSING;
    uint64_t cur_time = t_left;
    SetType(cur_time_q, INTEGER);
    void* val = EnvAddLong(CLIEnvironment, cur_time);
    SetValue(cur_time_q, val);
    EnvSetDefglobalValue(CLIEnvironment, cur_timeq_kw, &cur_time_q);

I partly took this approach from "Advanced Programming Guide" and it works fine, but I have some questions:

1. Does EnvAddLong(...) add a value, which will retain in memory, until the environment is destroyed? May it consume memory and increase the execution time of other API-functions like EnvRun(...), if the function with this fragment of code is called for, say, several thousand iterations?
2. Isn't it overkill? Should I go for something like EnvEval("(bind ...)") instead?

Answer 1

There's information in the CLIPS Advanced Programming Guide on how CLIPS handles garbage collection. API calls like EnvAddLong which are used to create values to pass to other API functions don't trigger garbage collection. Generally, API calls which cause code to execute or deallocate data structures such as Run, Reset, Clear, and Eval, trigger garbage collection and will deallocate any transient data created by functions like EnvAddLong. So if your program design repeatedly assigns values to globals and then runs, any CLIPS data structures you allocate will eventually be freed once the data is confirmed to be garbage and is no longer referenced by any CLIPS data structures.

If you can easily construct a string to pass to the Eval function, it's often easier to do this rather than make multiple API calls to achieve the same result.

The API was overhauled in release 6.4, so many tasks such as assigning a value to a defglobal can be done with one step rather than several.

   CLIPSValue rv;
   Defglobal *global;
   mainEnv = CreateEnvironment();

   Build(mainEnv,"(defglobal ?*x* = 3.1)");
   Eval(mainEnv,"?*x*",&rv);
   printf("%lf\n",rv.floatValue->contents);
   global = FindDefglobal(mainEnv,"x");
   if (global != NULL)
     {
      DefglobalSetInteger(global,343433);
      Eval(mainEnv,"(println ?*x*)",NULL);
      DefglobalGetValue(global,&rv);
      printf("%lf\n",rv.floatValue->contents);
     }