Find an Offset into a Structure

Find an Offset into a Structure

Here’s the code:

#define offset(a,b)  ((int) (&( ((a*)(0)) -> b)))

Step by step, here’s what it does:

  1. Type-cast 0, or NULL, into a pointer of type a. So a must be a typename.
  2. Member-select b from that pointer. So a must be a structure typename, and b some member property.
  3. Take the address of b. Since the a* used points to address 0, and b is some offset above the start of the a-structure, this means you’re getting the offset of b within a plus the address of a, which is zero. That is, you get the offset of b within a.
  4. Typecast that number to an integer.
Share the Post:
Heading photo, Metadata.

What is Metadata?

What is metadata? Well, It’s an odd concept to wrap your head around. Metadata is essentially the secondary layer of data that tracks details about the “regular” data. The regular

XDR solutions

The Benefits of Using XDR Solutions

Cybercriminals constantly adapt their strategies, developing newer, more powerful, and intelligent ways to attack your network. Since security professionals must innovate as well, more conventional endpoint detection solutions have evolved

AI is revolutionizing fraud detection

How AI is Revolutionizing Fraud Detection

Artificial intelligence – commonly known as AI – means a form of technology with multiple uses. As a result, it has become extremely valuable to a number of businesses across

AI innovation

Companies Leading AI Innovation in 2023

Artificial intelligence (AI) has been transforming industries and revolutionizing business operations. AI’s potential to enhance efficiency and productivity has become crucial to many businesses. As we move into 2023, several