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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