How to declare a pointer to structure element which is array structures

Question

 LStr, *LStrPtr, **LStrHandle structure is taken from LabView cintools extcode.h
   I used: sprintf(((*(*in_array)->Strings[*count])->str), local_str); to pass local_str string to
LabView array.  It worked fine, but  one programmer adviced me to change code to  be more readable.
Means - to change  (*(*in_array)->Strings[*count]) construction to a pointer. I tried many different
ways to implement this - but in all cases it caused LabView to crash. I understand that this question
is related to C programming not about LabView, but could you point me at a place where I have mistake ?
The most likely incorrect string is " LV_array = &(**((**in_array).Strings[*count])); "
Thanks in advance.
1.  typedef struct {
2.        int32   cnt;            /* number of bytes that follow */
3.        uChar   str[1];         /* cnt bytes */
4.  } LStr, *LStrPtr, **LStrHandle;
5.      
6.  typedef struct {
7.        int32 dimSize;
8.        LStrHandle Strings[1];
9.  } LVStringArray;
10.      
11. typedef LVStringArray **LVStrArrayHdl;
12.      
13  _declspec(dllexport) void avg_hello(int *count, LVStrArrayHdl in_array)
14.      {
15.      
16.       unsigned char *local_str="Entering function ma_in()";
17.       (*count) = 0;
18.       LStr* LV_array;
19.      
20.       LV_array = &(**((**in_array).Strings[*count])); //Set address to which should point LV_array
21.       subfunc(count, &in_array);                      // Call a function which resizes array (works)
22.       sprintf(LV_array->str, local_str);              //passing string to LabView (not working)
23.      
24. }
Solved!
Go to Solution.

Answer 1

thank you Andrey Dmitriev! spasibo!
With your example I understood where I have error in my code:
I tried to assign to pointer an address of string which wasn't yet pre-allocated!
that means simply swapping strings we get final code:
1.  typedef struct {
2.        int32   cnt;            /* number of bytes that follow */
3.        uChar   str[1];         /* cnt bytes */
4.  } LStr, *LStrPtr, **LStrHandle;
5.      
6.  typedef struct {
7.        int32 dimSize;
8.        LStrHandle Strings[1];
9.  } LVStringArray;
10.      
11. typedef LVStringArray **LVStrArrayHdl;
12.      
13  _declspec(dllexport) void avg_hello(int *count, LVStrArrayHdl in_array)
14.      {
15.      
16.       unsigned char *local_str="Entering function ma_in()";
17.       (*count) = 0;
18.       LStr* LV_array;
19.       subfunc(count, &in_array);                      // Call a function which resizes array (works), First we resize array, and only after that we can assign an address of string to a pointer
20.       LV_array = &(**((**in_array).Strings[*count]));  //Assigning address to which should point LV_array
21.      
22.       sprintf(LV_array->str, local_str);              //passing string to LabView (not working)
23.      
24. }