Apple disabled nested functions during their switchover to the Intel processors.
Xcode 2.2 says of nested functions: “Nested functions not supported in OS X 10.4.”.
Installing Xcode 2.3 installs version 4.0.1 of gcc (build 5341) that compiles and runs each of the several programs I have tested with nested functions but only if I say please by including the new gcc compile line option “-fnested-functions”.
I think this has to do with turning on the new x86 page table entry bit that disables instruction fetching from pages of the stack and heap.
I guess that they don’t do this if some of the loaded programs have been compiled with this option.
If you compile a target in Xcode with nested functions, Xcode passes on the compiler complaint about nested functions.
Xcode seems itself not to know about nested functions.
You must speak to it not of nested functions, but of compiler options.
You must do the following:
- In the main Xcode window, in the sub-window labeled “Groups & Files” turn down the triangle to the left of “Targets”
- For each target zot that includes code with nested functions double click that target which opens the window labeled “Target "zot" Info”.
- Select “Build”.
- Select “All Configurations” under “Configuration:” I suppose for this will be necessary for both testing and deployment.
- Select “GNU C/C++ Compiler 4.0” under “Collection:”.
I suppose that this causes subsequent actions to apply only when that compiler is used, as distinct from other compilers that can be used via Xcode.
- Scroll down to “Other C Flags” and double click.
- A new window should open in which to type text;
add the text “-fnested-functions” there and click OK.
- Close Target Info window, I suppose.
- Rebuild.
The above steps made gcc stop complaining and my apps ran again.
Here is the reason for all the fuss, I think.