我应该用emplace_back替换所有调用push_back？ [英] Should I replace all calls to push_back with emplace_back?

问题描述

在我的C ++应用程序中，我大量使用STL容器，如 vector 。有很多调用 push_back ，我一直关注不必要的构造和复制操作。

In my C++ application I heavily use STL containers like vector. There are a lot of calls to push_back, and I have been concerned about unnecessary constructions and copy operations.

我的应用程序是相当低级别，我非常关心CPU和内存使用。是否应该调用 emplace_back 来取代 push_back 的所有调用？

My application is pretty low-level and I am very concerned about CPU and memory usage. Should I replace all calls to push_back with calls to emplace_back?

我使用Visual Studio 2013。

I am using Visual Studio 2013.

推荐答案

我取代了所有调用 push_back 调用 emplace_back 并注意到以下内容：

I replaced all calls to push_back with calls to emplace_back and noticed the following:

• RAM使用（更新：这可能是由于其他效果）


• CPU使用率未变。


• 二进制文件稍小（x64）


• 没有兼容性问题。

• RAM usage is reduced by approximately 20% (update: this may have been due to other effects)
• CPU usage is unchanged
• The binary is slightly smaller (x64)
• There were no compatibility problems

这些经验我可以强烈推荐从 push_back 到 emplace_back 的移动，如果你的项目不需要向后 - 与旧编译器兼容。

Based on these experiences I can highly recommend to make the move from push_back to emplace_back if your project does not need to be backwards-compatible with older compilers.

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