CODEWITHSUNDEEP
objective-cdebuggingstructlldb
kris
kris

Reputation: 23591

Why is LLDB using the wrong field of my struct for arithmetic?

I'm using a struct from cocos3d called CC3IntPoint:

typedef struct {
  GLint x;    /**< The X-componenent of the point. */
  GLint y;    /**< The Y-componenent of the point. */
} CC3IntPoint;

When I run my program, it looks normal in the debugger:

(lldb) p pos
(CC3IntPoint) $5 = {
  (GLint) x = 48
  (GLint) y = 91
}
(lldb) p pos.y
(GLint) $6 = 91

However, if I do any math on pos.y, it uses pos.x! For example:

(lldb) p pos.y+1
(int) $7 = 49
(lldb) p pos.y*1
(int) $8 = 48

Am I missing something obvious here? Any ideas on how to fix?

Upvotes: 4

Views: 191

Answers (1)

bbum
bbum

Reputation: 162722

That looks very much like a bug.

Please file it.

I'd say this is some kind of pointer arithmetic magic, but I can't imagine that is the case.

If you really want to explore the issue, I would suggest grabbing the address of various sub-experssions and seeing if you can find where it decides to grab the wrong field.

See Jason's comment on the original question; that should really be the answer.

Upvotes: 2

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