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Got this code here that causes a seg fault. How do I prevent the seg fault from happening ( not the full code but just the part that is apparently causing it.)
unsigned char* pixel_offset = data + (j + width * i) * byte_per_pixel;
unsigned char y = pixel_offset[0];

What I have tried:

Searching on the internet and asking around on other different forums has turned up nothing so far.
Updated 23-Jan-23 18:07pm

1 solution

Segment faults are caused by attempting to address an invalid address. I will assume data is a pointer to the base of an image buffer. What you can do is check the validity of the rest of that expression. That means you can write a function that looks something like this :
int IsValidPixelOffset( int i, int j, int width, int bufferSize )
   int offset = ( j + width * i ) * byte_per_pixel;
   if( offset < bufferSize )
       return 1;       // valid offset

   return 0;           // invalid offset
Call this function before dereferencing the pointer and it should tell you if will you have a valid address or not. The function signature and implementation will likely have to change to suit your application. If it tells you the offset is correct and you still get a fault then your buffer was probably not allocated to be large enough.
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CPallini 24-Jan-23 2:24am    
Chillzy 24-Jan-23 10:26am    

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