[Flightgear-devel] CC compiler problem?

[Erik Hofman]

Hi,

I have a propblem with a peace of CC code which is pretty standard for 
common C. When I define a structure and point an array to a pre-defined 
array;

struct {
         string name;
         double (*fn)(double);
}  __fg_snd_[] =
{
  {"lin", _fg_lin},
  {"log", _fg_log10},
  {"", NULL}
};

this works for C but not for CC?
Am I doing something wrong here, or doesn't CC allow this type of 
declaration (and if not, is there an alternative)?

Erik


#include <stdio.h>
#include <math.h>
#include <string>

using std::string;

double _fg_lin(double v)   { return v; };
double _fg_log10(double v) { return (v < 1) ? 0 : log10(v+1); };

struct {
        string name;
        double (*fn)(double);
}  __fg_snd_[] =
{
 {"lin", _fg_lin},
 {"log", _fg_log10},
 {"", NULL}
};



int main() {
   double (*fn)(double) = NULL;

   for (int j=0; __fg_snd_[j].fn; j++) {
      printf("j = %i\n", j);
      if (__fg_snd_[j].name == "log") {
         fn = __fg_snd_[j].fn;
         break;
      }
   }

   if (!fn) {
      printf("fn = NULL\n");
      return -1;
   }

   printf("fn(0) = %f\n", fn(0));
   printf("fn(10) = %f\n", fn(10));

   
   return 0;
}


#include <stdio.h>
#include <math.h>
#include <string.h>

double _fg_lin(double v)   { return v; };
double _fg_log10(double v) { return (v < 1) ? 0 : log10(v+1); };

const struct {
        char name[3];
        double (*fn)(double);
} __fg_snd_[] =
{
   {"lin",  _fg_lin},
   {"log",  _fg_log10},

   {"", NULL}
};

int main() {
   double (*fn)(double);
   int j;

   for (j=0; __fg_snd_[j].fn; j++) {
      printf("j = %i\n", j);
      if (!strncmp(__fg_snd_[j].name, "log", 3)) {
         fn = __fg_snd_[j].fn;
         break;
      }
   }

   if (!fn) {
      printf("fn = NULL\n");
      return -1;
   }

   printf("fn(0) = %f\n", fn(0));
   printf("fn(10) = %f\n", fn(10));

   
   return 0;
}