Convert a pointer to void in a matrix

There are lots of C pointer and array declaration references on the internet. I'm a bit rusty on this type of declaration. I should be something like:

char (*matrix)[10][100];

Not sure why need to copy the buffer. Unless buffer gets overwritten. You could leave the data in place.

char (*matrix)[10][100];
matrix = buffer;
y = matrix[9][99]; // Last entry.

Or do your own arithmetic. Assuming buffer is an array of chars:

y = buffer[9*100+99]

Another way is to pass buffer into function. Something like:

void my_func(unsigned char matrix[10][100])
{
  int y;
  y = matrix[9][99];
}

main()
{
  unsigned char buffer[1000];
  my_function(buffer);
}

In your code fragment, matrix has not been initialized. I assume that you have as10signed some memory to it. Otherwise you might get some problems at runtime.

I'm sure others will have more elegant or better ways.

EDIT:

I think got the row vs column major thing wrong in doing your own arithmatric.

y = buffer[9 + 99*10]; // same as matrix[9][99]?