"In C, the default storage class of a non-local c o n s t is extern and in C++ it is static." (the quote is from: http://www.research.att.com/~bs/examples_short.pdf) My guess is that your "other" application may have used C++.
Therefore when you declare a const variable in a header in C you create storage in each compilation unit (.m or .c file) that you include the header in. Multiple storage for the same name => duplicate symbols linker error. You could possibly simply prefix your const declaration with "static" as in "static const unsigned x = 123;". THis still creates storage, and if you want compile time only constants, then you may consider staying with define or using a C++ compiler. Jesper On Sep 21, 2009, at 1:19 PM, Frederick C. Lee wrote: > I'm trying to replace #define directives with c datatype > directives.Example: > > (1) #define x 123 > > versus... > > (2) const unsigned x = 123; > > I place this at the top of the .h (or .m) file, outside of any class > or > method as stand alone. > > However, every time I try to use the (2) declaration (within a .h > file) the > linker gives the error: 'duplicate symbol _x in ....' > > I tried placing the (2) declaration at the top of a .m or .c file, > but I get > the same linker error. > > I've declared global constants in another application without a > problem. > > I've checked the compiler type within the build: gcc 4.2 > > What am I doing wrong? > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > Please do not post admin requests or moderator comments to the list. > Contact the moderators at cocoa-dev-admins(at)lists.apple.com > > Help/Unsubscribe/Update your Subscription: > http://lists.apple.com/mailman/options/cocoa-dev/jsbache%40adobe.com > > This email sent to jsba...@adobe.com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
