40

这是我在编译时收到的错误消息...

Ld /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Products/Debug-iphonesimulator/MasterDetail.app/MasterDetail normal i386
    cd /Users/ilia3546/Проекты/iDecide
    setenv IPHONEOS_DEPLOYMENT_TARGET 5.0
    setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.0.sdk -L/Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Products/Debug-iphonesimulator -F/Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Products/Debug-iphonesimulator -filelist /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetail.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=5.0 -framework UIKit -framework Foundation -framework CoreGraphics -o /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Products/Debug-iphonesimulator/MasterDetail.app/MasterDetail

duplicate symbol _main in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/main-E0BAF2CA88EDEE32.o
duplicate symbol _OBJC_IVAR_$_MasterDetailAppDelegate._window in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailAppDelegate-C2C06F734ECE2E36.o
duplicate symbol _OBJC_IVAR_$_MasterDetailAppDelegate._navigationController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailAppDelegate-C2C06F734ECE2E36.o
duplicate symbol _OBJC_IVAR_$_MasterDetailAppDelegate._splitViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailAppDelegate-C2C06F734ECE2E36.o
duplicate symbol _OBJC_CLASS_$_MasterDetailAppDelegate in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailAppDelegate-C2C06F734ECE2E36.o
duplicate symbol _OBJC_METACLASS_$_MasterDetailAppDelegate in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailAppDelegate-C2C06F734ECE2E36.o
duplicate symbol _OBJC_IVAR_$_MasterDetailDetailViewController._detailItem in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_IVAR_$_MasterDetailDetailViewController._TitleOfDetail in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_IVAR_$_MasterDetailDetailViewController._detailDescriptionLabel in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_IVAR_$_MasterDetailDetailViewController._masterPopoverController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_IVAR_$_MasterDetailDetailViewController.WebView in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_CLASS_$_MasterDetailDetailViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_METACLASS_$_MasterDetailDetailViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailDetailViewController-B3C32DC7B1BE4E38.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController._detailViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController._Controller1 in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfDecide in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfDecideOpis in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfGraph in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfGraphOpis in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfAbout in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_IVAR_$_MasterDetailMasterViewController.listOfAboutOpis in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_CLASS_$_MasterDetailMasterViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
duplicate symbol _OBJC_METACLASS_$_MasterDetailMasterViewController in:
    /Users/ilia3546/Library/Developer/Xcode/DerivedData/MasterDetail-fhgogwnbpzovbtaskgecptdnvgjs/Build/Intermediates/MasterDetail.build/Debug-iphonesimulator/MasterDetail.build/Objects-normal/i386/MasterDetailMasterViewController-A4C5EC1C14AE6E3A.o
ld: 23 duplicate symbols for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

appdelegate.m -

#import "MasterDetailAppDelegate.h"

#import "MasterDetailMasterViewController.h"

#import "MasterDetailDetailViewController.h"


@implementation MasterDetailAppDelegate

@synthesize window = _window;
@synthesize navigationController = _navigationController;
@synthesize splitViewController = _splitViewController;

- (void)dealloc
{
    [_window release];
    [_navigationController release];
    [_splitViewController release];
    [super dealloc];
}


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
            MasterDetailMasterViewController *masterViewController = [[[MasterDetailMasterViewController alloc] initWithNibName:@"MasterDetailMasterViewController_iPhone" bundle:nil] autorelease];
            self.navigationController = [[[UINavigationController alloc] initWithRootViewController:masterViewController] autorelease];
            self.window.rootViewController = self.navigationController; 
    } else {
        MasterDetailMasterViewController *masterViewController = [[[MasterDetailMasterViewController alloc] initWithNibName:@"MasterDetailMasterViewController_iPad" bundle:nil] autorelease];
        UINavigationController *masterNavigationController = [[[UINavigationController alloc] initWithRootViewController:masterViewController] autorelease];

        MasterDetailDetailViewController *detailViewController = [[[MasterDetailDetailViewController alloc] initWithNibName:@"MasterDetailDetailViewController_iPad" bundle:nil] autorelease];
        UINavigationController *detailNavigationController = [[[UINavigationController alloc] initWithRootViewController:detailViewController] autorelease];
        self.splitViewController = [[[UISplitViewController alloc] init] autorelease];
        self.splitViewController.delegate = detailViewController;
        self.splitViewController.viewControllers = [NSArray arrayWithObjects:masterNavigationController, detailNavigationController, nil];

        self.window.rootViewController = self.splitViewController;
    }
    [self.window makeKeyAndVisible];
    return YES;
}

- (void)applicationWillResignActive:(UIApplication *)application
{
    /*
     Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
     Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
     */
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    /*
     Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
     If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
     */
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    /*
     Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
     */
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    /*
     Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
     */
}

- (void)applicationWillTerminate:(UIApplication *)application
{
    /*
     Called when the application is about to terminate.
     Save data if appropriate.
     See also applicationDidEnterBackground:.
     */
}

@end

主.m -

//
//  main.m
//  MasterDetail
//
//  Created by Wei-Meng Lee on 3/9/11.
//  Copyright (c) 2011 __MyCompanyName__. All rights reserved.
//

#import <UIKit/UIKit.h>

#import "MasterDetailAppDelegate.h"

int main(int argc, char *argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([MasterDetailAppDelegate class]));
    }
}

我检查了导入 .m 文件而不是 .h，但一切都正确。

4

9 回答 9

92

检查您的导入文件，您可能正在导入一个.m文件。

#import "TimeModel.m"
于 2013-01-17T11:13:09.280 回答
60

在您的构建阶段，检查您是否多次编译同一个文件。即如果您搜索 main.m 它应该只返回一个结果。

如果这不是问题，您可以将 main.m 中的代码添加到问题中吗？

于 2012-10-20T13:42:52.493 回答
43

虽然以下不是 OP 案例中的原因，但它是我的，所以我会在这里分享给任何面临同样错误的人：

如果您在所有全局变量上都收到链接器错误，您可能需要extern在头文件中添加它们的声明。

缺少 extern 是否会产生此问题取决于构建设置，更具体地说，取决于“Apple LLVM - 代码生成”下的“No Common Blocks”（GCC_NO_COMMON_BLOCKS，-fno-common）。如果设置为 yes（这是 Xcode 较新版本中的默认设置），您将在没有extern.

为什么是外部？

extern关键字使它只是一个声明（即不是一个定义），因为它是一个头文件，这就是你想要的。一些编译器允许它不使用 extern 并且仍然“做正确的事情”，但不鼓励省略 extern。这就是为什么较新版本的 Xcode 默认启用警告的原因。

于 2015-06-04T09:51:10.687 回答
6

这是 Xcode 7.0 中出现重复符号错误的情况，以防其他人遇到这种情况

.h file

NSUserDefaults *defaults; // <----placing this above the @interface caused the issue

@interface someViewController

//...

改成

.h file

@interface someViewController

{
   NSUserDefaults *defaults;
}

//...
于 2015-10-06T21:10:38.020 回答
1

当您在具有不同实现的不同文件中具有相同的@interface 时，也可能发生这种情况。例如，您有一个 Player 类，在 Player.h/m 文件中，并且您有一个 Match 类 (Match.h/m)，并且匹配是在两个玩家之间，但不是前面提到的 Player。

播放器.h

@interface Player : NSObject
@property (nonatomic) NSUInteger _id;
@property (nonatomic, strong) NSString* firstName;
@property (nonatomic, strong) NSString* lastName;
@property (nonatomic, strong) NSString* username;
@end

匹配.h

@class Player

@interface Match : NSObject
@property (nonatomic, strong) Player* player1;
@property (nonatomic, strong) Player* player2;
@property (nonatomic) NSUInteger matchId;
@end

@interface Player : NSObject
@property (nonatomic, strong) NSString* nickName;
@property (nonatomic, strong) NSString* point;
@property (nonatomic, strong) NSNumber* lastMove;
@end

在这种情况下，编译器会看到两个不同的 Player 类实现。您需要将 Match.h 文件中的 Player 类重构为 MatchPlayer。

于 2014-05-26T11:19:06.490 回答
1

我遇到了一个typedef未添加到的问题，enum并且在 2 个文件之间出现了重复符号错误。

enum <name> {
 ...
} <name>;

通过在修复重复符号typedef之前添加。enum

于 2017-11-07T04:18:09.610 回答
0

就我而言，问题是 .m 文件被包含两次。

问题： 在此处输入图像描述

原因： 在此处输入图像描述

解决方案：只留下一个文件参考。

于 2015-06-12T09:43:48.973 回答
0

就我而言，我有相同的实体名称和 NSManagedObject 名称，并且未能在数据模型检查器中将实体类 Codegen 设置为“手动/无”。

于 2019-01-05T21:21:23.347 回答
0

如果这对其他人有帮助，那就是我的情况：

我想在 1 个头文件和实现文件中声明 2 个小类。

2 类正在使用 1 类

当我收到错误时，情况是这样的：
头文件 - 类 1 的接口+实现，类 2 的接口
实现文件 -类 2 的实现

在我将类 1 的实现从头文件移动到实现文件后，没有错误并且问题解决了：
头文件 - 类 1 的接口，类 2 的接口
实现文件 - 类 1 的实现，类 2 的实现

于 2018-07-29T19:03:35.293 回答