built-in

I was browsing through some codes at the end of the contest and found out that many people were using functions like __gcd(int,int) . What are these functions ? Similar functions include __builtin_popcount(int) __builtin_ctz(int) __builtin_clz(int) Where can I study about these functions ? Googling it didn't help much. Those are all GCC specifics. you can read about them here: http://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html#C-Extensions - but be aware, they're NOT C/C++ Standards. 来源： https://stackoverflow.com/questions/13443463/built-in-functions-in-c

Is it possible to replace some built-in python types with custom ones? I want to create something like: class MyInt(object): ... __builtin__.int = MyInt x = 5 Since you want to write a Pythonesque DSL, you have two options: Compile the code to an AST and walk the AST replacing nodes as appropriate. Build your own AST by hand. Once you have the AST you can go ahead and execute it directly. In either case, look at Python's Language Services for generation and manipulation of the AST. You seem to be asking if it's possible to override the type that is created when you enter literals . The answer

I've been thinking about the return values of these two functions. The __sync_bool_compare_and_swap function's return value seems to have obvious benefits, i.e. I can use it to tell whether the swap operation took place. However I can't see a good use of __sync_val_compare_and_swap's return value. Firstly, lets have a function signature for reference (from GCC docs minus the var args): type __sync_val_compare_and_swap (type *ptr, type oldval type newval); The problem I see is that the return value of __sync_val_compare_and_swap is the old value of the *ptr. To be precise, it's the value which

I can see various built-in functions (like __builtin_popount, __builtin_clz, etc) in the Xcode auto-completion pop-up. I'm not sure where these are getting picked up from though. Command clicking doesn't lead to a swift definition or any documentation. Are any __builtin_* or equivalent intrinsic functions available in Swift 3 and if so, what modules do I need to include and how can I call them? 来源： https://stackoverflow.com/questions/41353482/are-built-in-intrinsic-functions-available-in-swift-3

There is some python code that works under Linux. It uses the pwd module in a way like that: import pwd ... def func(): user=pwd.getpwnam(user)[2] Now we have a specific need to cover this code with tests, and tests have to be runnable under Windows. The program itself is intended to run only under Linux. The problem is that pwd module is not available under Windows, so the code under test will fail with ImportError, even if the implementation of pwd functions is mocked using MagicMock. The basic idea to solve this issue was to shadow the pwd module when running tests. So when running tests,

I heard something recently about it being included in Froyo and I was wondering if there was any truth to it. If there is, it would help me with an app idea greatly. kgiannakakis You are probably referring to the Adobe Reader , which is freely available for Android 2.1+. Some devices also have other applications pre-installed for rendering pdf files. See this question on how you can open the default pdf viewer from your application. Android has a built in framework from Android 5.0 / Lollipop, it's called PDFRenderer . There's an official example on Google's developer site: http://developer