What is Objective-C programming language
What is Objective -C and how is it different from other languagers like C,C++and java and what are its main uses.
1 comments
It is Smalltalk bolted onto C. Instead of garbage collection one uses reference counting.
While it does have exceptions, they don't unwind the stack as do C++ exceptions. They are commonly used only for fatal errors; I use C++ exceptions for all kinds of things that aren't really errors.
In C++, one calls a member function by dereferencing a pointer to that function from a table of such pointers.
In Objective-C, one calls a "method" by "sending it a message". That message is a small snippet of text. To dispatch to the actual function that implements the method, the Objective-C runtime (libobjc.dylib on OS X and iOS) must match the name of the method that one has targeted, to the name of the method whose implementation is actually just a regular C function.
Of course that would be very slow, but the Mach-O executable format is optimized for this case. Linux ELF and Windows COFF are not. So while in principle one can use Objective-C on Linux and Windows, the same code will run slower than on an equivalent Mac OS X box or iDevice.
Your code can send messages to methods that are not defined at compile time. If you actually call them you will terminate, but you can provide the implementation later.
I think Java can do that as well, but C and C++ do not have first-class language support for such a thing.
It's most-commonly used for Mac OS X Cocoa and iOS (iPhone, iPad and iPod Touch) Cocoa Touch GUI applications, but one can use it for GNUStep on *NIX as well as Cocotron on Windows.
While it does have exceptions, they don't unwind the stack as do C++ exceptions. They are commonly used only for fatal errors; I use C++ exceptions for all kinds of things that aren't really errors.
In C++, one calls a member function by dereferencing a pointer to that function from a table of such pointers.
In Objective-C, one calls a "method" by "sending it a message". That message is a small snippet of text. To dispatch to the actual function that implements the method, the Objective-C runtime (libobjc.dylib on OS X and iOS) must match the name of the method that one has targeted, to the name of the method whose implementation is actually just a regular C function.
Of course that would be very slow, but the Mach-O executable format is optimized for this case. Linux ELF and Windows COFF are not. So while in principle one can use Objective-C on Linux and Windows, the same code will run slower than on an equivalent Mac OS X box or iDevice.
Your code can send messages to methods that are not defined at compile time. If you actually call them you will terminate, but you can provide the implementation later.
I think Java can do that as well, but C and C++ do not have first-class language support for such a thing.
It's most-commonly used for Mac OS X Cocoa and iOS (iPhone, iPad and iPod Touch) Cocoa Touch GUI applications, but one can use it for GNUStep on *NIX as well as Cocotron on Windows.
Does it only run on Mac or it could run on windows.
Objective-C can be compiled and run on Windows, Linux, *BSD (ie. FreeBSD, OpenBSD and NetBSD), Solaris and Mac OS X.
You can run it on iOS Devices. You can't build it but must cross-compile on Mac OS X.
There are two compilers - GCC and clang/llvm. Apple's Xcode comes with clang/llvm, for the others one uses gcc.
There are three main things you need: the compiler, the runtime and the libraries.
You can run it on iOS Devices. You can't build it but must cross-compile on Mac OS X.
There are two compilers - GCC and clang/llvm. Apple's Xcode comes with clang/llvm, for the others one uses gcc.
There are three main things you need: the compiler, the runtime and the libraries.
Well thanks for helping me.
I'll send you my bill in the mail. :-D
If you're on windows, use Cocotron.
If you're on windows, use Cocotron.
haha sure...
Is there any way i could develop ios application in windows just for learning purpose without hackintosh my pc.
You'll need the iOS SDK. That can only be _installed_ on a Mac, but once installed, I understand you can copy it over to Windows.
However I've never actually tried doing so.
However I've never actually tried doing so.
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