Dear Gary,
The Help of Xcode says the returned C string is automatically freed just as
a returned object would be released. That means I don't need to release or
autorelease xmlStr?
Thanks,
Bing
On Sat, May 21, 2011 at 3:28 AM, Gary L. Wade
<garyw...@desisoftsystems.com>wrote:
> In your Xcode text window, hold down the option key and double click on
> NSString. You will be given the option of viewing an overview of the
> class. Click on the icon in the upper right side of the window that looks
> like a book. This will show you a view of the documentation for NSString.
> When looking at the documentation, click Command-F to do a search and
> enter "const char *" or a substring of that until you find the answer you
> want.
>
> Read the exceptions being thrown. Most likely it says something about
> autorelease pools. Do the same thing for the class it mentions that you
> did for NSString, albeit leaving out the particular point of searching for
> NSString.
>
> On 05/20/2011 12:04 PM, "Bing Li" <lbl...@gmail.com> wrote:
>
> >Dear Evadne and all,
> >
> >I appreciate so much for your replies!
> >
> >You change the return value from (const char *) to (NSString *). In my
> >system, since I need to send the XML to a server via BSD socket. I have to
> >convert it to (const char *).
> >
> >But I got another problem. If autoreleasing xmlStr or release xmlStr
> >before
> >returning the (const char *) value, the system got exceptions. Why?
> >
> >For this problem, I have to remove the lines. But how to manage the memory
> >of xmlStr?
> >
> >Best regards,
> >Bing
> >
> >On Fri, May 20, 2011 at 11:19 PM, Evadne Wu
> ><monocerosfu...@gmail.com>wrote:
> >
> >> Hi Bing,
> >>
> >> Re-factored this method a bit to try out some idea ‹ have a look? It¹s
> >> almost certainly asking for trouble to pass C strings around if you¹re
> >> working with Cocoa, but I am not sure of your scenario, so maybe I am
> >> (what¹s assumed to almost always be true) wrong with returning an
> >>NSString.
> >>
> >>
> >> + (NSString *) signInMessageWithPeerKey:(NSString *)aKey name:(NSString
> >> *)aName password:(NSString *)aPassword {
> >>
> >> NSParameterAssert(aKey && aName && aPassword);
> >>
> >> NSXMLNode *rootNode = [NSXMLNode
> >> elementWithName:MessageConstants.XML.MESSAGE_ROOT children:[NSArray
> >> arrayWithObjects:
> >>
> >> [NSXMLNode elementWithName:MessageConstants.XML.PEERKEY
> >> stringValue:aKey],
> >> [NSXMLNode elementWithName:MessageConstants.XML.PEERNAME
> >> stringValue:aName],
> >> [NSXMLNode elementWithName:MessageConstants.XML.PASSWORD
> >> stringValue:aPassword],
> >>
> >> nil] attributes:nil];
> >>
> >> NSXMLDocument *document = [[[NSXMLDocument alloc]
> >> initWithRootElement:rootNode] autorelease];
> >> [document setVersion:MessageConstants.XML.XML_VERSION];
> >> [document setCharacterEncoding:MessageConstants.XML.XML_ENCODING];
> >>
> >> return [[[NSString alloc] initWithData:[document
> >> XMLDataWithOptions:NSXMLNodePrettyPrint] encoding:[document
> >> characterEncoding]] autorelease];
> >>
> >> }
> >>
> >>
> >> -ev
> >>
> >> On May 20, 2011, at 22:43, Bing Li wrote:
> >>
> >> > Dear Jeff and all,
> >> >
> >> > I appreciate so much for your help! After reading the document from
> >> > apple.com, I changed my code as follows. It must be fine.
> >> >
> >> > Best regards,
> >> > Bing
> >> >
> >> > + (const char *) CreateSignInMessage: (NSString *)peerKey PN:
> >>(NSString
> >> > *)peerName PW:(NSString *)password
> >> > {
> >> > NSXMLElement *root = [NSXMLNode
> >> > elementWithName:MessageConstants.XML.MESSAGE_ROOT];
> >> > NSXMLDocument *xmlDoc = [[NSXMLDocument alloc]
> >> > initWithRootElement:root];
> >> > [xmlDoc setVersion:MessageConstants.XML.XML_VERSION];
> >> > [xmlDoc
> >>setCharacterEncoding:MessageConstants.XML.XML_ENCODING];
> >> >
> >> > NSXMLElement *peerKeyElement = [NSXMLNode
> >> > elementWithName:MessageConstants.XML.PEERKEY];
> >> > [root addChild:peerKeyElement];
> >> > [peerKeyElement addChild:[NSXMLNode
> >>textWithStringValue:peerKey]];
> >> >
> >> > NSXMLElement *peerNameElement = [NSXMLNode
> >> > elementWithName:MessageConstants.XML.PEERNAME];
> >> > [root addChild:peerNameElement];
> >> > [peerNameElement addChild:[NSXMLNode
> >> textWithStringValue:peerName]];
> >> >
> >> > NSXMLElement *passwordElement = [NSXMLNode
> >> > elementWithName:MessageConstants.XML.PASSWORD];
> >> > [root addChild:passwordElement];
> >> > [passwordElement addChild:[NSXMLNode
> >> textWithStringValue:password]];
> >> >
> >> > NSData *data = [xmlDoc
> >>XMLDataWithOptions:NSXMLNodePrettyPrint];
> >> > NSString *xmlStr = [[NSString alloc] initWithData:data
> >> > encoding:NSUTF8StringEncoding];
> >> > const char *xmlChar = [xmlStr UTF8String];
> >> >
> >> > /*
> >> > [passwordElement release];
> >> > [root release];
> >> > [xmlStr release];
> >> > [data release];
> >> > */
> >> > [xmlDoc release];
> >> > [xmlStr autorelease];
> >> > return xmlChar;
> >> > }
> >> >
> >> >
> >> > On Thu, May 19, 2011 at 4:23 PM, Jeffrey Walton <noloa...@gmail.com>
> >> wrote:
> >> >
> >> >> On Wed, May 18, 2011 at 2:16 PM, Ken Thomases <k...@codeweavers.com>
> >> wrote:
> >> >>> On May 18, 2011, at 12:55 PM, Bing Li wrote:
> >> >>>
> >> >>>> NSXMLElement *root = [NSXMLNode
> >>elementWithName:"MessageRoot"];
> >> >>>
> >> >>> As per Cocoa's memory management conventions, you don't not own the
> >> >> object returned by -[NSXMLNode elementWithName:]. You have not
> >>invoked
> >> a
> >> >> method whose name contains "alloc", "new", or "copy" or which is
> >> explicitly
> >> >> documented as giving its caller ownership rights and
> >>responsibilities.
> >> >>>
> >> >>>> NSXMLElement *peerKeyElement = [NSXMLNode
> >> >> elementWithName:"PeerKey"];
> >> >>>
> >> >>> Same here.
> >> >>>
> >> >>>> NSXMLElement *peerNameElement = [NSXMLNode
> >> >> elementWithName:"PeerName"];
> >> >>>
> >> >>> Same here.
> >> >>>
> >> >>>> NSXMLElement *passwordElement = [NSXMLNode
> >> >> elementWithName:"Password"];
> >> >>>
> >> >>> Same here.
> >> >>>
> >> >>>> NSData *data = [xmlDoc
> >>XMLDataWithOptions:NSXMLNodePrettyPrint];
> >> >>>
> >> >>> Same here.
> >> >>>
> >> >>>> [passwordElement release];
> >> >>>> // [peerNameElement release];
> >> >>>> // [peerKeyElement release];
> >> >>>> [root release];
> >> >>>> [xmlDoc release];
> >> >>>> [xmlStr release];
> >> >>>> [data release];
> >> >>>
> >> >>> Many of these releases are wrong, not just the ones you have
> >>commented
> >> >> out.
> >> >>> Of these, you only own xmlDoc and xmlStr, so those are the only ones
> >> you
> >> >> are
> >> >>> entitled to release. If you didn't happen to get exceptions from
> >> >> releasing the
> >> >>> others, it was an unhappy accident. (Unhappy because it hid your
> >>bug.
> >> >> It is
> >> >>> always better for bugs to be found early.)
> >> >> If it helps Bing (and coming from someone who frequently needs the
> >> >> same sort of help): (1) Run you code using Instruments, or (2) select
> >> >> Executable -> Arguments and add NSZombieEnabled = YES. Both should
> >> >> help you flush out the problems early (as Ken suggests).
> >> >>
> >> >>> Please review the Memory Management Programming Guide <
> >> >>
> >>
> >>
> http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Mem
> >>oryMgmt/
> >> >.
> >> >> It explains all of this.
> >> >>>
> >> >> Also grab a book or two. It will help you digest it. Nuremberg's book
> >> >> would be a good choice since the doctor stays active on this list.
> >> >>
> >> >> Jeff
> >> >>
> >> > _______________________________________________
> >> >
> >> > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
> >> >
> >> > Please do not post admin requests or moderator comments to the list.
> >> > Contact the moderators at cocoa-dev-admins(at)lists.apple.com
> >> >
> >> > Help/Unsubscribe/Update your Subscription:
> >> > http://lists.apple.com/mailman/options/cocoa-dev/ev%40monoceroi.com
> >> >
> >> > This email sent to e...@monoceroi.com
> >>
> >>
> >_______________________________________________
> >
> >Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
> >
> >Please do not post admin requests or moderator comments to the list.
> >Contact the moderators at cocoa-dev-admins(at)lists.apple.com
> >
> >Help/Unsubscribe/Update your Subscription:
> >
> http://lists.apple.com/mailman/options/cocoa-dev/garywade%40desisoftsystem
> >s.com
> >
> >This email sent to garyw...@desisoftsystems.com
>
>
>
_______________________________________________
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to arch...@mail-archive.com
