Getting a runtime exception

-(BOOL)createTimer
{
    stRs232Timer*   pEvent = malloc(sizeof(stRs232Timer));

    pEvent->bPersistent = YES;                              // setup timer structure
    pEvent->wAppTimerId = 95;
    pEvent->uPeriod     = 50;
    pEvent->bStopped    = NO;
    pEvent->uExpirationTime = 10;

    NSLog(@"bPersistent:%d",pEvent->bPersistent);
    NSLog(@"wAppTimerId:%d",pEvent->wAppTimerId);
    NSLog(@"uPeriod:%d",pEvent->uPeriod);
    NSLog(@"bStopped:%d",pEvent->bStopped);


    NSData* myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];

    wTimerId = 99;
    pEvent->uPeriod = 51;
    myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];
         [m_cAppIdMap setObject:myData forKey:[NSNumber numberWithUnsignedShort:wTimerId]];
    wTimerId = 96;
    pEvent->uPeriod = 52;
    myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];
    [m_cAppIdMap setObject:myData forKey:[NSNumber numberWithUnsignedShort:wTimerId]];
    wTimerId = 97;
    pEvent->uPeriod = 53;
    myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];
    [m_cAppIdMap setObject:myData forKey:[NSNumber numberWithUnsignedShort:wTimerId]];
    wTimerId = 98;
    pEvent->uPeriod = 54;
    myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];
    [m_cAppIdMap setObject:myData forKey:[NSNumber numberWithUnsignedShort:wTimerId]];
    wTimerId = 95;
    pEvent->uPeriod = 55;
    myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];
    [m_cAppIdMap setObject:myData forKey:[NSNumber numberWithUnsignedShort:wTimerId]];

    NSLog(@"The dictionary count now is:%d",[m_cAppIdMap count]);
    NSLog(@"The dictionary values now is:");
    NSLog(@"%@",m_cAppIdMap);

    [m_cPendingEventList addObject:myData];
    NSLog(@"EventList:%@",m_cPendingEventList);

    [self ChangeTimer:95 withPeriod:10];

    free(pEvent);
    return YES;
}

-(BOOL)ChangeTimer:(unsigned short)wTimerIds withPeriod:(uint8_t)uPeriod
{
 stRs232Timer*   pEvent;
    NSLog(@"Into the changeTimer");
    pEvent = (stRs232Timer*)[m_cAppIdMap objectForKey:[NSNumber numberWithUnsignedShort:wTimerIds]];
    NSLog(@"The val is:%@",pEvent);
    if(pEvent!=nil){
        pEvent->bStopped = NO;
        pEvent->uPeriod = uPeriod;
        NSLog(@"completed");
        }       

    return YES;
}

main.m
----------
int main (int argc, const char * argv[]) {

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSArray1* arr = [[NSArray1 alloc]init];
    [arr createTimer];
    [pool drain];
    return 0;
}

I am getting EXC_BAD_ACCESs runtime exception.Why is it so.I am not accessing any released memory.

EDITED:

2011-05-30 11:21:45.191 NSArray[1091:a0f] bPersistent:1
2011-05-30 11:21:45.194 NSArray[1091:a0f] wAppTimerId:95
2011-05-30 11:21:45.195 NSArray[1091:a0f] uPeriod:50
2011-05-30 11:21:45.195 NSArray[1091:a0f] bStopped:0
2011-05-30 11:21:45.196 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110180 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.196 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x1001102f0 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.197 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110410 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.197 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110a70 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.198 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110ab0 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.198 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110ad0 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.199 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110b10 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.199 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110b30 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.200 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100110b70 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.201 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x1001109e0 of class NSConcreteData autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.201 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x1001105d0 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.202 NSArray[1091:a0f] The dictionary count now is:5
2011-05-30 11:21:45.202 NSArray[1091:a0f] The dictionary values now is:
2011-05-30 11:21:45.203 NSArray[1091:a0f] {
    98 = <5f000136 000a0000>;
    97 = <5f000135 000a0000>;
    96 = <5f000134 000a0000>;
    99 = <5f000133 000a0000>;
    95 = <5f000137 000a0000>;
}
2011-05-30 11:21:45.203 NSArray[1091:a0f] EventList:(
    <5f000137 000a0000>
)
2011-05-30 11:21:45.204 NSArray[1091:a0f] Into the changeTimer
2011-05-30 11:21:45.204 NSArray[1091:a0f] *** __NSAutoreleaseNoPool(): Object 0x100111130 of class NSCFNumber autoreleased with no pool in place - just leaking
2011-05-30 11:21:45.205 NSArray[1091:a0f] The val is:<5f000137 000a0000>
2011-05-30 11:21:45.205 NSArray[1091:a0f] completed

This is 开发者_开发问答the output i'm getting when removed the NSAutoreleasePool and [pool drain].

If i'm not removing both of this i'm getting EXC_BAD_ACCESS as the run time exception.When i debugged i got exception(EXC_BAD_ACCESS) coming when it comes to [pool drain]; statement.

I could not find out why this happens.

look at this line (and similar):

NSData* myData = [NSData dataWithBytes:(stRs232Timer*)pEvent length:sizeof(stRs232Timer*)];

the amount of bytes is equal to the size of a pointer to stRs232Timer data, which for exmaple for a 32-bit system would be 4 bytes, for 64-bit system 8 bytes - but not the size of stRs232Timer structure. So you are copying not enough bytes.

The cast is also not necessary, so it should be like that:

NSData* myData = [NSData dataWithBytes: pEvent length: sizeof(stRs232Timer)];

BTW this very first instance will be overwritten before it gets saved into the dictionary.

LATER

In ChangeTimer you should use NSData bytes method instead of casting directly to stRs232Timer:

pEvent = (stRs232Timer*)[[m_cAppIdMap objectForKey:[NSNumber numberWithUnsignedShort:wTimerIds]] bytes];

This will give you the pointer to the data, casting NSData directly to stRs232Timer is wrong.