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I couldn't find documentation that supports Clang offering the __builtin_apply intrinsics, but their availability would make a C objc_msgSend somewhat more pala

by DHowett 10y ago

I couldn't find documentation that supports Clang offering the __builtin_apply intrinsics, but their availability would make a C objc_msgSend somewhat more palatable.

groovy2shoes 10y ago
Ah. I don't mean to be too argumentative. You've helped me to understand why objc_msgSend() could not be done in standard C, and I thank you for that :) However, in the case of GCC's ObjC implementation, I don't see why it couldn't be implemented in GCC's dialect, thus obviating any need for assembly. Pardon me while I reflect on (and lament) the fact that we're still stuck using such crude and ancient tools for systems programming...
- lilyball 10y ago
  FWIW, it appears that Mulle-objc gets around this by actually changing the calling convention for Obj-C methods, so the IMP takes a single parameter (beyond self and _cmd) which is a struct that contains all of the method parameters. This way the compiler can just synthesize the struct for you, and then objc_msgSend() itself can be written in C because it just needs to pass the pointer to the struct along to the IMP rather than messing about with forwarding arbitrary arguments.
  - groovy2shoes 10y ago
    Interesting. Thanks!