IOS SDK中提供了一个现成的函数 NSSetUncaughtExceptionHandler 用来做异常处理，但功能非常有限，而引起崩溃的大多数原因如：内存访问错误，重复释放等错误就无能为力了，因为这种错误它抛出的是Signal，所以必须要专门做Signal处理。首先定义一个UncaughtExceptionHandler类，代码如下：

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface UncaughtExceptionHandler : NSObject
{
    BOOL dismissed;
}
+(void) InstallUncaughtExceptionHandler;
@end

//利用 NSSetUncaughtExceptionHandler，当程序异常退出的时候，可以先进行处理，然后做一些自定义的动作，比如下面一段代码，就是网上有人写的，直接在发生异常时给某人发送邮件，</span>
void UncaughtExceptionHandlers (NSException *exception);

#import "UncaughtExceptionHandler.h"
#include <libkern/OSAtomic.h>
#include <execinfo.h>
NSString * const UncaughtExceptionHandlerSignalExceptionName = @"UncaughtExceptionHandlerSignalExceptionName";
NSString * const UncaughtExceptionHandlerSignalKey = @"UncaughtExceptionHandlerSignalKey";
NSString * const UncaughtExceptionHandlerAddressesKey = @"UncaughtExceptionHandlerAddressesKey";
volatile int32_t UncaughtExceptionCount = 0;
const int32_t UncaughtExceptionMaximum = 10;
const NSInteger UncaughtExceptionHandlerSkipAddressCount = 4;
const NSInteger UncaughtExceptionHandlerReportAddressCount = 5;
NSString* getAppInfo()
{
    NSString *appInfo = [NSString stringWithFormat:@"App : %@ %@(%@)\nDevice : %@\nOS Version : %@ %@\n",
                         [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"],
                         [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"],
                         [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"],
                         [UIDevice currentDevice].model,
                         [UIDevice currentDevice].systemName,
                         [UIDevice currentDevice].systemVersion];
    //                         [UIDevice currentDevice].uniqueIdentifier];
    NSLog(@"Crash!!!! %@", appInfo);
    return appInfo;
}


void MySignalHandler(int signal)
{
	int32_t exceptionCount = OSAtomicIncrement32(&UncaughtExceptionCount);
	if (exceptionCount > UncaughtExceptionMaximum)
	{
		return;
	}
    if(signal==11)
    {//比较坑爹的是 我遇到的一个问题只有iPhone5出现问题 但是我这边测试的没有iPhone5 无法直接log  可能是内存不足 果然 删除几个应用就可以了 所以加了这句

        UIAlertView * tip2 = [[UIAlertView alloc]initWithTitle:@"可能原因:key" message:@"内存不足" delegate:nil cancelButtonTitle:@"ok" otherButtonTitles:nil];
        [tip2 show];
        [tip2 release];
    }
	
    NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithObject:[NSNumber numberWithInt:signal] forKey:UncaughtExceptionHandlerSignalKey];
	NSArray *callStack = [UncaughtExceptionHandler backtrace];
	[userInfo setObject:callStack forKey:UncaughtExceptionHandlerAddressesKey];
	[[[[UncaughtExceptionHandler alloc] init] autorelease]
     performSelectorOnMainThread:@selector(handleException:)
     withObject:
     [NSException
      exceptionWithName:UncaughtExceptionHandlerSignalExceptionName
      reason:
      [NSString stringWithFormat:
       NSLocalizedString(@"Signal %d was raised.\n"
                         @"%@", nil),
       signal, getAppInfo()]
      userInfo:
      [NSDictionary
       dictionaryWithObject:[NSNumber numberWithInt:signal]
       forKey:UncaughtExceptionHandlerSignalKey]]
     waitUntilDone:YES];

}


@implementation UncaughtExceptionHandler
+(void) InstallUncaughtExceptionHandler
{
	signal(SIGABRT, MySignalHandler);
	signal(SIGILL, MySignalHandler);
	signal(SIGSEGV, MySignalHandler);
	signal(SIGFPE, MySignalHandler);
	signal(SIGBUS, MySignalHandler);
	signal(SIGPIPE, MySignalHandler);
}
+ (NSArray *)backtrace
{
    void* callstack[128];
    int frames = backtrace(callstack, 128);
    char **strs = backtrace_symbols(callstack, frames);
    int i;
    NSMutableArray *backtrace = [NSMutableArray arrayWithCapacity:frames];
    for (
         i = UncaughtExceptionHandlerSkipAddressCount;
         i < UncaughtExceptionHandlerSkipAddressCount +
         UncaughtExceptionHandlerReportAddressCount;
         i++)
    {
	 	[backtrace addObject:[NSString stringWithUTF8String:strs[i]]];
    }
    free(strs);
    return backtrace;
}
- (void)alertView:(UIAlertView *)anAlertView clickedButtonAtIndex:(NSInteger)anIndex
{
	if (anIndex == 0)
	{
		dismissed = YES;
	}
}
- (void)handleException:(NSException *)exception
{
	UIAlertView *alert =
    [[[UIAlertView alloc]
      initWithTitle:NSLocalizedString(@"Unhandled exception", nil)
      message:[NSString stringWithFormat:NSLocalizedString(
                                                           @"You can try to continue but the application may be unstable.\n"
                                                           @"%@\n%@", nil),
               [exception reason],
               [[exception userInfo] objectForKey:UncaughtExceptionHandlerAddressesKey]]
      delegate:self
      cancelButtonTitle:NSLocalizedString(@"Quit", nil)
      otherButtonTitles:NSLocalizedString(@"Continue", nil), nil]
     autorelease];
	[alert show];
	CFRunLoopRef runLoop = CFRunLoopGetCurrent();
	CFArrayRef allModes = CFRunLoopCopyAllModes(runLoop);
	while (!dismissed)
	{
		for (NSString *mode in (NSArray *)allModes)
		{
			CFRunLoopRunInMode((CFStringRef)mode, 0.001, false);
		}
	}
	CFRelease(allModes);
	NSSetUncaughtExceptionHandler(NULL);
	signal(SIGABRT, SIG_DFL);
	signal(SIGILL, SIG_DFL);
	signal(SIGSEGV, SIG_DFL);
	signal(SIGFPE, SIG_DFL);
	signal(SIGBUS, SIG_DFL);
	signal(SIGPIPE, SIG_DFL);
	if ([[exception name] isEqual:UncaughtExceptionHandlerSignalExceptionName])
	{
		kill(getpid(), [[[exception userInfo] objectForKey:UncaughtExceptionHandlerSignalKey] intValue]);
	}
	else
	{
		[exception raise];
	}
}
void UncaughtExceptionHandlers (NSException *exception) {
    NSArray *arr = [exception callStackSymbols];
    NSString *reason = [exception reason];
    NSString *name = [exception name];
    NSString *urlStr = [NSString stringWithFormat:@"mailto://1140454645@qq.com?subject=bug报告&body=感谢您的配合!<br><br><br>"
                        "错误详情:<br>%@<br>--------------------------<br>%@<br>---------------------<br>%@",
                        name,reason,[arr componentsJoinedByString:@"<br>"]];
    NSURL *url = [NSURL URLWithString:[urlStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    [[UIApplication sharedApplication] openURL:url];
    
    //或者直接用代码，输入这个崩溃信息，以便在console中进一步分析错误原因
    NSLog(@"1heqin, CRASH: %@", exception);
    NSLog(@"heqin, Stack Trace: %@", [exception callStackSymbols]);
}

@end

 [UncaughtExceptionHandler InstallUncaughtExceptionHandler];
    NSSetUncaughtExceptionHandler (&UncaughtExceptionHandlers);