我应该使用long long或为的int64_t便携式code？ [英] Should I use long long or int64_t for portable code?

问题描述

我有一个是写在C和C ++的开放源代码codeBase的。我在寻找这是保证是一个整数类型的至少的64位宽，可与开源的C可靠地编上最OS X（英特尔64位）和Linux系统和C ++编译器，而对最终用户的部分太多额外的工作。 Windows和32位客户端的支持并不重要，在这个时候。

I have an open-source codebase that is written in both C and C++. I'm looking for an integer type that is guaranteed to be at least 64 bits wide, which can be reliably compiled on most OS X (Intel, 64-bit) and Linux boxes with open-source C and C++ compilers, without too much extra work on the end user's part. Windows and 32-bit client support are not important at this time.

我没有在OS X上一些测试，并附带的开发工具不支持C + 11模式（因此似乎并不保证长长）。锵不支持此项工作，要么，虽然它支持长长如果启用C99模式，经过一定的版本。

I did some testing on OS X, and the latest GCC that ships with the developer tools does not support C+11 mode (and therefore does not seem to guarantee availability of long long). Clang does not support this, either, though it supports long long if C99 mode is enabled, after a certain version.

时，一般建议使用的int64_t 代替长长，当便携性是一个重要的目标是什么？使用格式说明似乎痛苦。

Is the general suggestion to use int64_t in place of long long, when portability is an important goal? Using the format specifiers seems painful.

我可以可靠地投了的int64_t 到长长（以及同样的符号等效采用 uint64_t中）以与利用现有功能和库使用长长作为参数？ （和回来的，当然。）

Can I reliably cast an int64_t to long long (and likewise to the unsigned equivalent with uint64_t) to use it with existing functions and libraries that take long long as parameters? (And back again, of course.)

在那种心境下，如果我船code，需要锵功能不是在GCC，是锵将会取代GCC作为首选的Linux上的编译器？提供源$ C ​​$ C给最终用户时，是什么编译器，我可以预料，在大多数情况下，？

In that frame of mind, if I ship code that requires Clang functionality not in GCC, is Clang going to replace GCC as the compiler of choice on Linux? Is that compiler something I can expect, for the most part, when offering source code to end users?

基本上，我想问问从谁使用这两种类型的便携式C和C ++ code其他开发商，谁可能有什么可能是更好的长期的路要走一些建议，一些建议，鉴于上述目标的记在心里。

Basically, I'd like to ask for some advice from other developers who have used both types for portable C and C++ code, who might have some suggestions on what might be the better long-term way to go, given the above goal in mind.

推荐答案

类型长长和无符号长长是标准C和标准C ++类型与至少64位。所有的编译器我知道提供这些类型的，可能除了当在 -pedantic 模式，但在这种情况下，的int64_t 或 uint64_t中将是不可用的pre-C ++编译器2011，无论是。在所有的系统＆LT; stdint.h＆GT; 是可用的，太。也就是说，只要我可以告诉它并没有多大关系如何拼写的类型。 1所述的主要目标; stdint.h＆GT; 是为特定比特数提供最佳匹配。如果你需要至少64位，但你也想采取禁食实施这一类型的优势，你会使用 int_least64_t 或 uint_least64_t 从＆LT; stdint.h＆GT; 或＆LT; cstdint＆GT; （在后一种情况下， ，该名在命名空间中定义 STD ）。

The types long long and unsigned long long are standard C and standard C++ types each with at least 64 bits. All compilers I'm aware of provide these types, except possibly when in a -pedantic mode but in this case int64_t or uint64_t won't be available with pre-C++ 2011 compilers, either. On all of the systems <stdint.h> is available, too. That is, as far as I can tell it doesn't matter much how you spell the type. The main goal of <stdint.h> is to provide the best match for a specific number of bits. If you need at least 64 bit but you also want to take advantage of the fasted implementation of such a type, you'd use int_least64_t or uint_least64_t from <stdint.h> or <cstdint> (in case of the latter, the names are defined in namespace std).

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