compile-time

问题 I am getting this error: "error: unable to spawn process (Argument list too long) ** ARCHIVE FAILED ** The following build commands failed: CompileSwiftSources normal arm64 com.apple.xcode.tools.swift.compiler (1 failure) Exitcode =65 " I went through this link: Xcode export localization throws error "Argument list too long" This article provides a good temporary solution of the problem stating to reduce the path hierarchy. But this does not seem to be an appropriate approach. Can anyone

问题 I want to generate unique numbers for each class in my header, primes in my case primes but let's say this should only be consecutive numbers i.e. 1,2,3,4,etc. Of course I can hardcode these: struct A { enum { ID = 1; }; }; struct B { enum { ID = 2; }; }; struct C { enum { ID = 3; }; }; struct D { enum { ID = 4; }; }; This is very error-prone since in reality the classes are not that small and if I add a new class in the middle I have to change all the following numbers if I don't want to

问题 Context I am working on an instrumenting profiler, that enables you to name different measurements by string. So for example: MEASURE_SCOPE(text_rendering_code); ... MEASURE_SCOPE(password_hashing); ... MEASURE_START(system_call); ... MEASURE_STOP(system_call); where the macros would be defined like this: #define MEASURE_START(name) save_start_event(get_timestamp(), #name); #define MEASURE_STOP(name) save_stop_event(get_timestamp(), #name); #define MEASURE_SCOPE(name) Profiling_Class object#

问题 Is there a Java equivalent to the C & C++ compile-time constants __DATE__ and __TIME__. I need to print compile time and version info of the program being compiled. Thanks kodev19 回答1: As far as i know, there is nothing like that. But on a running JVM you can get a few informations straight away from the jar using something like the code below (here, the information comes from the Manifest file put in the jar at compilation time (which ever your build system is, Ant or Maven or anything else)

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Is it possible to write a C++ template to check for a function's existence? say there are 2 classes: struct A{ int GetInt(){ return 10; } }; struct B{ int m; }; I want to use object of type A or B in following function tempate< typename T > int GetInt( const T & t ) { //if it's A, I'll call: return t.GetInt(); //if its' B, I'll call: return t.m; } Now, because there are whole bunch of classes, some contain

问题 Why does the C++ compiler makes it possible to declare a function as constexpr, which can not be constexpr? For example: http://melpon.org/wandbox/permlink/AGwniRNRbfmXfj8r #include <iostream> #include <functional> #include <numeric> #include <initializer_list> template<typename Functor, typename T, size_t N> T constexpr reduce(Functor f, T(&arr)[N]) { return std::accumulate(std::next(std::begin(arr)), std::end(arr), *(std::begin(arr)), f); } template<typename Functor, typename T> T constexpr

问题 Consider the following class, with the inner struct Y being used as a type, eg. in templates, later on: template<int I> class X{ template<class T1> struct Y{}; template<class T1, class T2> struct Y{}; }; Now, this example will obviously not compile, with the error that the second X<I>::Y has already been defined or that it has too many template parameters. I'd like to resolve that without (extra) partial specialization, since the int I parameter isn't the only one and the position of it can

问题 I'm currently trying to create a C source code which properly handles I/O whatever the endianness of the target system. I've selected "little endian" as my I/O convention, which means that, for big endian CPU, I need to convert data while writing or reading. Conversion is not the issue. The problem I face is to detect endianness, preferably at compile time (since CPU do not change endianness in the middle of execution...). Up to now, I've been using this : #if __BYTE_ORDER__ == __ORDER_LITTLE

问题 I want know the number of Array elements at compile time: let sections = ["A","B","C"] // I want fill later this Array with Arrays of type Product var productsInSection = [[Product]](count:number of Array elements from sections array, repeatedValue:[]) my question is what I can use for: " number of Array elements from sections array " so I don't must have a look, if I change anytime let sections = ["A","B","C","D"] 回答1: I don't understand why you need "compile time". But I think count

问题 I'd like to obscure strings at compile time. I know it can be done in other preprocessors but I haven't found a way to do this with the C preprocessor. 回答1: Well, you can do it, but it's ugly. #define ENCODE_STRING_14(str) {\ str[0] ^ 0x020,\ str[1] ^ 0x020,\ str[2] ^ 0x020,\ str[3] ^ 0x020,\ str[4] ^ 0x020,\ str[5] ^ 0x020,\ str[6] ^ 0x020,\ str[7] ^ 0x020,\ str[8] ^ 0x020,\ str[9] ^ 0x020,\ str[10] ^ 0x020,\ str[11] ^ 0x020,\ str[12] ^ 0x020,\ '\0'\ } void Decode( char *str, int length ) {