strings over the network as c style structs

sneaky · 09-09-2011, 08:08 AM

I'm communicating over the network using c style structs. This is working for ints & the like as I'm passing the real value. I can't figure out how to pass a string over.

I have tried variations of

Code:

typedef struct {
	Message message;
	uint32_t cost;
	const char *costName;
} MessageCost;

I have only been able to declare this as a pointer, which obviously won't work on the other end.

the receiver then has:

Code:

else if (message->messageType == kMessageTypeCost) {     

		MessageCost *messageCost = (MessageCost *) [data bytes];
		NSLog(@"Received: %@", messageCost->costName);

I'm getting a bad access getting the cost name as it's a pointer to memory that isn't valid on this device.

I'm creating the string:

Code:

	message.costName = [name UTF8String];

(name is just a NSString)

so this will work fine if I'm passing the string within the same device where the memory is valid but how do I do this between devices?

thanks!

sneaky · 09-09-2011, 08:50 AM

Figured it out.

Code:

typedef struct {
	Message message;
	uint32_t cost;
	char costName[kMaxMessageLength];
} MessageCost;

Create the message:

Code:

MessageCost message;
...
[name getCString:message.costName maxLength:kMaxMessageLength encoding:NSUTF8StringEncoding];

Receive the message:

Code:

...
        MessageCost *messageCost = (MessageCost *) [data bytes];
        NSString *name = [[NSString alloc] initWithCString:messageCost->costName encoding:NSUTF8StringEncoding];
#ifdef _DEBUG
        NSLog(@"Received: %@", name);