Segmentation fault error in function using 3D dynamic array - c

Question

I'm working on a code which purpose is to manipulate a 1D array coming from a 3D array. Showing the code will explain everything:
First of all, I'm working with array of structures:
typedef struct range_in_memory {
double E, R;
} RANGE;
And I wrote this function that works like a charm when called in simple debug implementation:
RANGE *dq_Eloss_load_range_file (double Aion, double Zion, double Atar, double Ztar, int *n){
char *filename;
char errormsg[80], dummy;
int N = 2;
int i = 0;
FILE *fp;
RANGE *memrange;
filename = (char*)malloc (50*sizeof (char));
dq_Eloss_set_filename (filename, Aion, Zion, Atar, Ztar);
fp = dq_myfopen (filename, "r", errormsg);
while ( !feof (fp) ){
fscanf (fp, "%c", &dummy);
if (dummy == '\n') {
N++;
}
}
rewind (fp);
memrange = (RANGE*) calloc (N, sizeof (RANGE));
while ( !feof (fp) ){
fscanf (fp, "%lf\t%lf\n", &memrange[i].E, &memrange[i].R);
i++;
}
*n = N;
// for (i=0; i<N; i++){
// printf ("\n%lf %lf", memrange[i].E, memrange[i].R);
// }
fclose (fp);
return (memrange);
}
The commented for cycle is crucial, so keep it in mind.
Now, coming to my problem, I need to use a 3D array like:
RANGE ***memrangeTAR;
The function *dq_Eloss_load_range_file loads the content of a file int an array of RANGE type. I want to do this for several files, which are named according to two parameters Aion and Zion. In my mind it would have been something like:
(double) memrangeTAR [Aion][Zion][i].E
(double) memrangeTAR [Aion][Zion][i].R
which would have been the values in the i-th line in the file related to Aion and Zion.
This is the code:
void dq_load_range_files (RANGE ***memrangeTAR){
int NTAR;
double *ZMAX;
int Aion, Zion, AMAX = 250.;
int i;
printf ("\n Allocating Memory for range data..."); fflush (stdout);
ZMAX = (double*) malloc ((AMAX+1)*sizeof (double));
memrangeTAR = (RANGE***) malloc ((AMAX+1)*sizeof (RANGE**));
for (Aion=1; Aion<=AMAX; Aion++){
ZMAX[Aion] = ceil (dq_range_table_get_max_Zion (Aion));
memrangeTAR [Aion] = (RANGE**) malloc ((ZMAX[Aion]+1)*sizeof(RANGE*));
}
printf (" ...ALLOCATED! \n\n");
printf ("\n Loading range data...\n"); fflush (stdout);
for (Aion=1; Aion <=AMAX; Aion++){
for (Zion=1; Zion<=ZMAX[Aion]; Zion++){
memrangeTAR [Aion][Zion] = dq_Eloss_load_range_file ((double)Aion, (double)Zion, cor_sosau16.mass.Mtar, cor_sosau16.charge.Ztar, &NTAR);
// for (i=0; i<N; i++){
// printf ("\n%lf %lf", memrangeTAR[Aion][Zion][i].E, memrangeTAR[Aion][Zion][i].R);
// }
}
}
}
It compiles (gcc on unix machine using gnu99 standard). It runs unless i try to access to the 3D array. If I de-comment the printing cycle in the first function, I can get what I want: it prints on terminal the content of the current file. If I de-comment the for cycle in the second function, it gives me segmentation fault.
What am I doing wrong?

Answer 1

I somehow managed to solve but not to understand WHY it's a solution.
By defining a
RANGE *tmp;
variable, calling the usual function as
tmp = dq_Eloss_load_range_file ((double)Aion, (double)Zion, cor_sosau16.mass.Mtar, cor_sosau16.charge.Ztar, &NTAR);
and then assigning wanted pointer:
memrangeTAR[Aion][Zion] = tmp;
I can use the content of the variables in any way now, like:
for (i=0; i<N; i++){
printf ("\n%lf %lf", memrangeTAR[Aion][Zion][i].E,
memrangeTAR[Aion][Zion][i].R);
}
In this way no segmentation fault error is encountered, making me think that the problem was the way I was passing the pointer to the function, but still don't understand...