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84

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I'm trying to figure out whether I can build a static library that hides all of its internal objects and functions, etc, except for the interfaces I want to export. I'm experimenting with Xcode (gcc 4.2).

I've used the __attribute__((visibility("hidden"))) attribute on some C++ classes per this documentation. I've also defined little helper C functions as being file-local (static), etc.

However, when I run strings on the resulting .a library file, even when compiled in Release configuration, I still see the names of my ostensibly-hidden classes, with their method names, and even the names of file-local functions strewn around in there as well.

I've added the -fvisibility=hidden and even -fno-rtti to the gcc flags. While this reduces some of the strings, the class names, method names, and static functions names are all still in there in plain or mangled-but-readable form.

Is there a reliable way to get the compiler to build this stuff without having the string names of all the internal stuff emitted into the binary? It shouldn't be necessary to have for any external clients linking in.

(To clarify: I'm asking about obfuscation of internal naming, versus literal export binding needs. I'm disconcerted that all the internal workings are visible via the strings command, regardless of whether these symbols are formally exported or not.)

Thanks.

+1  A: 

You can't hide symbols in static libraries; you need shared libraries for that.

Gregory Pakosz
Can you elaborate?
quixoto
a static library is just a collection of .o files, and the names need to be present until link time
Gregory Pakosz
see also this solution that works under Linux for instance http://stackoverflow.com/questions/1601900/dont-expose-symbols-from-a-used-library-in-own-static-library/1681781#1681781 -- unfortunately there is no objcopy for Mac nor iOS
Gregory Pakosz
But why are translation-unit-local (static) functions present by name in the .o files?
quixoto