My defined constants are giving me 'undeclared identifier' issues. I have them in a Constants.h file that I am including in my .pch file. I thought it might be something with my .pch file, however, if I delete it from there and try #import it in one of the classes where I need one of the constants, then I still get an 'undeclared identifier' error.
If I take each #define line and put them at the top of the .m class file directly, they work. So my syntax is correct.
So it's something with the .h file itself, but I have no idea what.
//
// Constants.h
// Sliding Drawer
#define kOffscreenX 320 // X coord when Sliding Drawer is offscreen
#define kVisibleX 40 // X coord when Sliding Drawer is visible
// WordlistButton
#define kNumScores 3
// Fonts
#define kMessageFontSize 14
#define kScoreFontSize 10
It's impossible to see the error only from this piece of code. Preprocessor tends to create very messy things, especially when there are circular imports involved.
You can try to delete the current compiled version of the header, note it's not in the derived data folder, it's in XCode's cache (see Project -> Build Setttings -> Precompiled Headers Cache Path).
However, if you have tried to import Constants.h directly and it didn't work, the problem may be somewhere else.
Are you sure there is only 1 file called Constants.h? Note you should use a prefix for your files (e.g. SAConstants.h if Smooth Almonds is your name) to avoid collision with Apple's headers or headers of the libraries you are using.
If you import the header directly, go to the .m file and tap on Product -> Generate Output -> Preprocessed File and find Constants.h import in it. Is it your header?
By the way, there is a nice article about avoiding this kind of things in precompiled headers http://qualitycoding.org/precompiled-headers/
I found this thread due to an other error upper case parameter in my define statement. I solved it for my issue with lower casing:
#define MSB(BTvalue) ((uint8_t) (BTvalue >> 8)) //threw this error
changing BTvalue to just value with lowercase parameter made me happy
#define MSB(value) ((uint8_t) (value >> 8))
Related
This question already has an answer here:
Force Header Files to Compile as C++ in Xcode
(1 answer)
Closed 2 years ago.
I'm trying to use a 3rd party sample code as part of my Objective-C application.
However, when trying to compile my project I get a lot of compiler errors.
The objc syntax that is used in the sample is quite strange and I believe that it is compiled as something else within the project.
For example, as part of the header file the struct definition has default values:
File.h
struct Options
{
int count = 100;
}
...
In their project, the above header file would compile just fine, but when I try to compile it I see an Xcode error:
Expected ';' at end of declaration list
I'm not an objective-c expert, but from what I've read and also found as part of other posts data types cannot have default values, but somehow it compiles fine in the Xcode sample app.
Please let me know if you need more info or other examples of what would compile fine in their project and doesn't work when I copy and paste the code into mine.
Edit:
Force Header Files to Compile as C++ in Xcode
Individually header files doesn't compiled. Compiled source files where they included. If you include them in .c they will be compiled like C, if in .m - like Objective-c, if in .cpp - like C++, if in .mm - like Objective-C++.
My issue was that I was using this header file into a .m file which compiles it to an Objective-C standard. When I change the extension to .mm everything worked fine.
When you think of objective-C as actually being C its more clear why defaults are not set in .h files
This does not apply to the rules of default sizes which are needed when no flexible memory allocation for a data type is available by default, like for (as is) most data types in C.
Even this two sentences already show the difficulty to distinguish what is meant with "default".
Which is why you end up with definition of initiation processes and functions to declare what exactly is "default" in the other file.
#ifdef __cplusplus
extern "C" {
#endif
typedef struct {
int count;
} Options;
typedef struct {
int foo;
Options bar[100];
} Foo;
struct Bar {
Foo lotsof;
}
void MyInitiationFunction(Bar *b);
// definition of MyInitiationFunction in .m/.c file
#ifdef __cplusplus
}
#endif
but there is the concept of enum that can trick your mind where defined enumeration default states are what you build some stuff on, which is not a value.
I have a subclass of NSObject, but I have a problem with header file, when I run the project, it shows me this:
and it allows me to add this, but directly this logical error is returned: "#end must appear in Objective-C context"
I precise that with Xcode6 I didn't have that issue with this Does anyone knows how to fix this frustrating issue ?
EDIT:
that's a constants file, do not pay attention to the file's name, here is .m file:
#import "CUSBoxes.h"
const int defaultCount = 10;
const long int repeat = 25000;
const NSString *defaultDescription = #"If any layout issue is related, change default values of each box you want to display";
#implementation CUSBoxes
#end
Usually this error causes you missed #end or invalid character in one of the .h file you used in your project. I have came across with this error, this error not exist in same files it throws check for other header files to fix this issue.
1) You might missing #end in any of the Header file.Check one by one all .h file which has #interface section,should be ended with "#end".
2) If everything looks good then Try cleaning project or Restart Xcode.(In my case,It worked).
When I clean, build and run my XCode project all goes well, but if I open a file that calls the function, an Use of undeclared identifier 'func()' appears. This is the whole implementation:
The function is called:
func();
And 'func()' is decleared in a .h file like so:
#if __cplusplus
extern "C" {
#endif
extern void func();
#if __cplusplus
}
#endif
and func() is implemented is a cplusplus library.
Why would the error ONLY appears if the file is open, but if I don't open it, it runs and works just fine?
Xcode has two ways of generating error messages. Usually both of these generate the same messages, so you do not detect that there are two systems.
The first system is the editor which does syntax coloring and auto-completion. It will also show error messages almost instantly after you write an error.
The second system is errors shown in the build log.
I suspect that your project has a complicated include setting. This prevents the first system from finding the correct file to include and therefore it cannot find the definition of func().
I'm getting this error:
/Class/GData/OAuth/GDataOAuthViewControllerTouch.m:116:22: Expected a type
That line is:
authentication:(GDataOAuthAuthentication *)auth
Inside of this block of code:
- (id)initWithScope:(NSString *)scope
language:(NSString *)language
requestTokenURL:(NSURL *)requestURL
authorizeTokenURL:(NSURL *)authorizeURL
accessTokenURL:(NSURL *)accessURL
authentication:(GDataOAuthAuthentication *)auth
appServiceName:(NSString *)keychainAppServiceName
delegate:(id)delegate
finishedSelector:(SEL)finishedSelector {
NSString *nibName = [[self class] authNibName];
I'm a newb XCode developer. So far I've created and compiled a calculator app based from an online class but that's it.
Is this a library that is not being included?
Background: The previous developer abandoned the project and the owner sent the project code to me. I'm trying to replace the existing graphics with new graphics and recompile it with support for iOS 6, which I thought I should be able to do without any coding, but have run into this error and many others when I opened the project. I have the latest XCode.
The :22 (and the position of the caret within the editor) tell you exactly where on the line the error is. In this case it's telling you that where it sees GDataOAuthAuthentication it was expecting a type. So, implicitly, it doesn't recognise that GDataOAuthAuthentication is a type.
Objective-C still sits upon compilation units ala C — each .m file is compiled in isolation then the lot are linked together. You use #import (or #include if you want; #import just guarantees the same file won't be included twice) to give each individual file visible sight of any external definitions it needs.
So, that's a long-winded way of reaching the same conclusion as Rick did five minutes ago: you've probably omitted a necessary #import.
A few things to look for:
Did you #import the file where the GDataOAuthAuthentication type is defined? (e.g. #import "GDataOAuthAuthentication.h")
Is there a variable named GDataOAuthAuthentication which is causing the compiler to think GDataOAuthAuthentication is a variable not a type?
I'm trying to configure cocoalumberjack and when I've added ddLogLevel set to LOG_LEVEL_VERBOSE XCode throws "use of undeclared identifier" error. Why is that? How to avoid?
This question indicates that clearing DerivedData and restarting Xcode solves this kind of error.
However you should not include variables in the pre-compiled header as it will be included in every source file and prefix files are somewhat complicated compared to normal header files.
Better is to have use a Constants.h file which contains:
extern int ddLogLevel;
and #import that into your prefix file.
Then create an Constants.m with:
int ddLogLevel =
#ifdef DEBUG
LOG_LEVEL_VERBOSE;
#else
LOG_LEVEL_ERROR;
#endif
This way there is only one instance of ddLogLevel and it can be easily changed at runtime if necessary.
See this question for hints about prefix file best practices.
What solved it for me was changing #import <CocoaLumberjack/CocoaLumberjack.h> to #import CocoaLumberjack;, when using Xcode 8.0 for an Objective-C project.
Droppy’s post is correct and I recommend doing that, but I would like to address the question directly. There is a flaw in your code that may be resulting in the error.
LOG_LEVEL_VERBOSE is defined in DDLog.h. Your header file only imports DDLog.h if __OBJC__ is defined, but uses LOG_LEVEL_VERBOSE without this condition. Therefore if __OBJC__ is not defined, LOG_LEVEL_VERBOSE will be undefined.
Why would __OBJC__ not be defined? The prefix header is prepended to C, C++, Objective-C and Objective-C++ files. Since __OBJC__ is only defined for the latter two, if there are any C or C++ files in your project then the error will occur.
Knowing this, it is clear the ddLogLevel definition should be inside the #ifdef __OBJC__ check. However, you should do what Droppy said, and also make sure all Objective-C imports go inside the check.
For people who use "CocoaLumberjack 2.X" and still facing same issue after pod update, please try to import "DDLegacyMacros.h".
For prefix file users, try something like this :
#ifdef __OBJC__
...
...
#import <DDTTYLogger.h>
#import <DDLog.h>
#import <DDLegacyMacros.h>
#endif
Hope this helps someone else.