I'm writing code which has a lot of 1 & 2 dimensional arrays. I got "error: can't allocate region" and I think its because too much memory is allocated. I use "malloc" and "free" functions, but I'm not sure I'm using them correclyt. Maybe you know where I could see good examples on memory management in C?
so.. I just trying to get one algorithm work and for now this code is just function after function..
//memory allocation for 1D arrays
buffer = malloc(num_items*sizeof(double));
//memory allocation for 2D arrays
double **cross_norm=(double**)malloc(150 * sizeof(double *));
for(i=0; i<150;i++)
{
cross_norm[i]=(double*)malloc(num_items*sizeof(double));
}
//code
Window(N, window_buffer);
STFTforBMP(buffer,N,f, window_buffer);
getMagnitude(buffer,f, N, magnitude);
calculateEnergy(flux,magnitude, f);
calculateExpectedEnergy(expected_flux, candidate_beat_period, downbeat_location, f);
calculateCrossCorrelation(cross, flux, expected_values, f);
findLargestCrossCorrelation(&cross_max, cross, f);
normalizeCrossCorrelation(cross_norm, &cross_max, cross, f);
...............
How should I use the free
function?
You have to free()
the allocated memory in exact reverse order of how it was allocated using malloc()
.
Note that You should free the memory only after you are done with your usage of the allocated pointers.
memory allocation for 1D arrays:
buffer = malloc(num_items*sizeof(double));
memory deallocation for 1D arrays:
free(buffer);
memory allocation for 2D arrays:
double **cross_norm=(double**)malloc(150 * sizeof(double *));
for(i=0; i<150;i++)
{
cross_norm[i]=(double*)malloc(num_items*sizeof(double));
}
memory deallocation for 2D arrays:
for(i=0; i<150;i++)
{
free(cross_norm[i]);
}
free(cross_norm);