In my application I'm using a static library named ABC.a in that library in a c file named Layout.c there is a function called init(). And I linked the library to the projects and added the .h file. The program is compiled without error but while linking the function its throwing the error. Why?
Info: I've added that static library in build phases also.
And the library is built for armv7, armv7s and arm64. bitcode enabled: No and Build active architectures : NO
Example error:
Undefined symbols for architecture arm64:
"AMID_INIT(int*, int*, int)", referenced from:
-[ViewController microphone:hasAudioReceived:withBufferSize:withNumberOfChannels:] in Test_lto.o
"amid_Val(float const*, int, int*, int, unsigned int)", referenced from:
-[ViewController microphone:hasAudioReceived:withBufferSize:withNumberOfChannels:] in Test_lto.o
Please help two days gone for this.
This is based on the fact that you mention that the .a file is generated from a c file. The linker error:
"AMID_INIT(int*, int*, int)", referenced from:
-[ViewController microphone:hasAudioReceived:withBufferSize:withNumberOfChannels:] in Test_lto.o
indicates that the AMID_INIT definition came from a C++/Objective-C++ file - this is because C files would not have information about the parameters of the routine.
From this I was able to surmise that the library header file did not have c++ guards.
Three approaches in this case - wrap all imports of the library header file in the C++ code with something like:
extern "C" {
#import "lib.h"
}
or create a lib.hpp file, containing:
#pragma once
extern "C" {
#import "lib.h"
}
and #import 'lib.hpp' instead, or fix the lib.h file by adding the standard name mangling preventative:
… near start of lib.h:
#ifdef __cplusplus
extern "C" {
#endif
… near end of lib.h:
#ifdef __cplusplus
}
#endif
This allows you to keep using the lib.h with both C and C++ compilers by declaring that all the routines offered by lib.h are exposed using C linkage, rather than C++ linkage.
Related
Define a method in the .mm file
#if defined(__cplusplus)
extern "C"{
#endif
extern void UnitySendMessage(const char* obj, const char* method, const char* msg) __attribute__ ((weak));;
extern NSString* _CreateNSString (const char* string);
#if defined(__cplusplus)
}
#endif
#interface UnityAdapter ()
...
Called in #implementation UnityAdapter()
UnitySendMessage("PottingMobile", "bannerDidLoadAd", "");
I need help solving the following error:
ld: warning: Could not find auto-linked framework 'FBSDKCoreKit'
Undefined symbols for architecture armv7:
"_UnitySendMessage", referenced from:
-[UnityAdapter bannerDidLoadAd] in UnityAdapter.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
when i don't use UnitySendMessage method， everthing is ok.
I want to write a framework for bridging unit and iOS projects. When I use it in a unit packaged project, no problem. When I put the bridging file into my own framework, I will report an error. There is nothing in the framework project. Do I need to integrate unit's lib? If so, how to integrate? Can you give me a website? Thank you.
Unity is currently doing this with their library feature.
You can look at their solution.
If you need a solution now: Have a look at https://github.com/jiulongw/swift-unity. It's all automated and a good starting point, but missing the library feature.
This project shows how to make an actual library: https://github.com/forestlin1212/unity-ios-framework (But for an older Unity version and not automated)
The app I've been working on uses an external library, pdlib, which has it's own externals (.c files) which I've been importing via the bridging header #import "Uzi.c" and calling in my main Swift file via Uzi.c's setup function Uzi_setup() in my ViewController class. I've had no problem with this until after updating to new public Xcode 8 a few days ago (I had no problem with Xcode 8 Beta 1 over the Summer).
Here are the 7 errors I get, listed under a single "Mach-O Linker Error" umbrella:
Undefined symbols for architecture x86_64:
"_Uzi_bang", referenced from:
_Uzi_setup in ViewController.o
"_Uzi_class", referenced from:
_Uzi_setup in ViewController.o
"_Uzi_float", referenced from:
_Uzi_setup in ViewController.o
"_Uzi_new", referenced from:
_Uzi_setup in ViewController.o
"_Uzi_pause", referenced from:
_Uzi_setup in ViewController.o
"_Uzi_resume", referenced from:
_Uzi_setup in ViewController.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Those undefined symbols are 6 functions and a class declare from Uzi.c. Here's a link to the whole c file: https://github.com/electrickery/pd-miXedSon/blob/master/hammer/Uzi.c
I've tried every solution I've found online for dealing with similar problems, with no solution yet... I tried changing the "Architecture" and "Valid Architecture" settings to only armv7 and armv7s (no arm64) and changed "Build Active Architecture Only" to "No". These step seem to help others in similar situations, but they didn't work for me (and taking away arm64 causes additional errors to appear).
XCode 8 is pretty recent (the public version was released Sept. 13), so there are virtually no other questions about this upgrade causing a similar problem.
Any help would be greatly appreciated!
Solved by #danomatika on GitHub: https://github.com/libpd/libpd/issues/149
"You generally shouldn't include/import an implementation file aka .c, .cpp, .m, etc. This is what is causing the duplicate symbol issue.
This is what the "forward function declaration" in the header file is for: to tell the compiler that a function exists and what data it takes/returns. The compiler then assumes the actual implementation of the function exists in an implementation file. If it can't be found, then you get an "undefined symbol error." If you somehow end up declaring the function twice, aka include both a header with the forward declaration and the implemetaton of the function itself in the .c file, then you get a "duplicate symbol error."
This is all lower-level stuff that is only really an issue since Pd externals are designed around being dynamic libraries, so are not built or provided with headers which include the function declarations. This is why you have to do a little extra work and do it yourself.
Their are two easy fixes for this, both of which involve declaring the required function you want to call from the .c file in a header file.
Simply declare the function in the bridging header:
void uzi_setup();
Create a header, say Externals.h, and declare all of the externals stuff there:
// forward declare setup functions only found in .c implementations
void uzi_setup();
// convenience wrapper function
void externals_setup() {
uzi_setup();
}
Then import the file in your bridging header:
#import "Externals.h"
And in swift, you can now do:
externals_setup()
I'm getting the following error when trying to use C's math.h library:
#import <Foundation/Foundation.h>
#import <math.h>
#interface Filter : NSObject {
float cutoff;
float resonance;
float sampleRate;
float *f;
float freq;
float damp;
}
- (float)filter:(float)input;
#end
Can you tell me how I can solve this error? It seems that the min() function cannot be compiled to armv7 architectures.
Undefined symbols for architecture armv7:
"_min", referenced from:
-[Filter init] in Filter.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
You are linking against a static library that is compiled for i386 or x86-64, in your specific case I think that you have referenced a library that contains min function but is not compiled for armv7 architecture, take a look at your referenced static library .
On iOS I had to use fmin() instead of min() as alex purposed. Further, i didn't even need to import math.h as Anoop said.
I'm trying to use an iOS native framework inside Unity, but I don't know how.
Inside my C# script, I call a native function like this :
[DllImport ("__Internal")]
private static extern void writeHello();
void Start () {
writeHello();
}
I have drag the iOS framework inside my project like this :
Link to my image
But when I deploy my app on iPad, xCode showing this error :
Undefined symbols for architecture armv7: "_writeHello", referenced
from:
RegisterMonoModules() in RegisterMonoModules.o ld: symbol(s) not found for architecture armv7 clang: error: linker command failed with
exit code 1 (use -v to see invocation)
I don't understand why, and I don't know if what I'm trying to do is possible.
Help! :)
Thanks,
Sennin
The iOS framework must be put in the xCode generated project, not in unity.
And the framework's functions must be wrapped in an extern "C" block (as shown here).
Then you will be able to use it in C# with dllimport.
The doc says that all files with extensions .a,.m,.mm,.c,.cpp located in the Assets/Plugins/iOS folder will be merged into the generated Xcode project automatically. The docs also says that subfolders are currently not supported, so, in your example, the "framework-helloUnity.framework" folder will be ignored.
It is important to note that .m files default to C-style bindings, while .mm files default to C++-style bindings. In other word, unless you use the extern "C" keyword, as Heilo suggested, your functions won't be found if you put them in .mm or .cpp files.
In other words, if you put the following:
void writeHello() {}
in a file named Assets/Plugins/iOS/myTestFile.m, your code should compile.
Found the solution thanks to this post : Calling Objective-C method from C++ method?
By doing like that :
void myWriteHello( void *test) {
[(id)test writeHello];
}
- (void) writeHello
{
NSLog(#"Hello World!");
}
and calling my C function from Unity
You have write the following function in your Xcode project any class
extern "C"
{
-(void) writeHello
{
}
}
I am new to Objective-C and a bit rusty at using C++ and templates, and I am not sure why I am having this link error.
I have a header file that contains definitions similar to these:
struct Info {
std::string name;
};
typedef std::map<std::string, Info> InfoMap;
void Validate(InfoMap* infoMap);
#interface InfoValidator : NSObject
{
}
+(InfoValidator*) getInstance;
-(void) validate:(InfoMap*)infoMap;
#end
I also have an .mm file that contains the following definition for the (global) Validate() method:
void Validate(InfoMap* infoMap)
{
[[InfoValidator getInstance] validate:infoMap];
}
When I call Validate() from a C++ class (defined in an .mm file), I receive the following error:
Undefined symbols for architecture armv7:
Validate(std::map<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, Info, std::less<std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, > std::allocator<std::pair<std::basic_string<char, std::char_traits<char>, ?> std::allocator<char> > const, Info> > >*)",
referenced from:
ItemInterface::ValidateItems(int, char const**)in iteminterface.o
ld: symbol(s) not found for architecture armv7
collect2: ld returned 1 exit status
The file has been added to the project, and it is the only link error I get. Thanks for any help.
Did you rename Market_Validate to Validate for the code you've quoted here? The link error refers to the former, which doesn't exist in the code given.
If so, the code looks correct in isolation, I suspect there's something outside the code you've shown going wrong. Make sure both .mm files are in fact being compiled and linked. Check that both include the same header file with your Validate() function declaration. Since you have renamed the function before posting it here, make sure you're using the same name for it throughout your code (specifically, the declaration and definition must match exactly).
Are you using namespaces anywhere? Make sure you didn't accidentally put your function definition inside a namespace if the declaration isn't - they'll be referring to different functions.
Note that the code as you've posted it won't compile, as there's a semicolon missing after your struct Info definition. It's often impossible to help once the code has been altered for the question without testing that the problem still exists with that code. If you're still stuck, I suggest trying to amend the code in this question so it will compile and show the same link error. If you can't reproduce it, take a good look at the differences between your 'real' code and the question code.