问题
I am currently using Xcode 4, and in my .pch file I have this macro:
#define localize(s) NSLocalizedString((s), nil).
When I try to use this macro in some .m file, I receive this warning: Implicit declaration of function 'localize' is invalid in C99.
This code compiles without a problem, but how can I fix this so I don't get a warning?
回答1:
I had this problem when I did a global replace of NSLog with DLog. I foolishly included the
#define DLog(...) NSLog(...
statements, so I ended up with
#define DLog(...) DLog(...
which caused the warnings, and a linker error.
回答2:
Implicit function declarations are those that the compiler sees the first time used as a function call (as opposed to those where a prototype or the function definition is seen first).
Apparently your code used localize(foo) but the macro definition was not visible. Possible reasons: you forgot to #include the file containing the localize macro or the precompilation of headers went south an did not include the localize macro so it was left unexpanded.
回答3:
Another "foolish" mistake I ran into was the fact that my DLog was defined in the prefix header of the iOS target, so I had to copy it over to the prefix of the OSX target, as well...
回答4:
I had this problem because I accidentally imported CocoaLumberjack like this:
#import <CocoaLumberjack/DDLog.h>
Apparently the CocoaLumberjack team modularized the code some more; and macros like DDLogError are now defined separately in their own header file.
I replaced the import statement with this and the error went away:
#import <CocoaLumberjack/CocoaLumberjack.h>
回答5:
In my case only one file was giving this error. Turned out that I added it to the project's tests target membership (in the File Inspector on the right).
来源：https://stackoverflow.com/questions/6704335/implicit-declaration-of-function-c99