How to cast C struct just another struct type if their memory size are equal?

Posted by Eonil on Stack Overflow See other posts from Stack Overflow or by Eonil
Published on 2010-05-02T09:28:48Z Indexed on 2010/05/02 9:37 UTC
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I have 2 matrix structs means equal data but have different form like these:

// Matrix type 1.
typedef float Scalar;
typedef struct { Scalar e[4]; } Vector;
typedef struct { Vector e[4]; } Matrix;

// Matrix type 2 (you may know this if you're iPhone developer)
struct CATransform3D
   {
   CGFloat m11, m12, m13, m14;
   CGFloat m21, m22, m23, m24;
   CGFloat m31, m32, m33, m34;
   CGFloat m41, m42, m43, m44;
};
typedef struct CATransform3D CATransform3D;

Their memory size are equal. So I believe there is a way to convert these types without any pointer operations or copy like this:

// Implemented from external lib.
CATransform3D CATransform3DMakeScale (CGFloat sx, CGFloat sy, CGFloat sz);
Matrix m = (Matrix)CATransform3DMakeScale ( 1, 2, 3 );

Is this possible? Currently compiler prints an "error: conversion to non-scalar type requested" message.

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How to cast C struct just another struct type if their memory size are equal? - Developer IT

How to cast C struct just another struct type if their memory size are equal?

c

struct

cast

Related posts about c

Related posts about struct

copying a struct with a struct member to another struct

Error in installing ZTE AC2738 on ubuntu 3.0.0-12-generic

Core-audio - constructing an AudioBufferList struct (Q about c struct definition)

flexible length struct array inside another struct using C

Union struct produces garbage and general question about struct nomenclature

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