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post |
第145期 |
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本期文章由 黄亮Anthony HNY 赞助
2024 01 07
标准委员会动态/ide/编译器信息放在这里
编译器信息最新动态推荐关注hellogcc公众号 本周更新 2024-01-03 第235期
看个乐呵, 了解概念对于CPU运行还是有点理解的
LLVM知识，学吧，都是知识，早晚碰到
jemalloc最新知识，学吧
编译很慢，怎么抓？
#include <fmt/core.h>
int main() {
fmt::print("Hello, {}!\n", "world");
}
// c++ -ftime-trace -c hello.cc -I include -std=c++20ftime-trace的数据可以放到浏览器的tracing里，比如 chrome://tracing/
我没看懂他是怎么分析出头文件的耗时的，总之，把string前向声明一下
#ifdef FMT_BEGIN_NAMESPACE_STD
FMT_BEGIN_NAMESPACE_STD
template <typename Char>
struct char_traits;
template <typename T>
class allocator;
template <typename Char, typename Traits, typename Allocator>
class basic_string;
FMT_END_NAMESPACE_STD
#else
# include <string>
#endif但是这种接口编译不过
template <typename... T>
FMT_NODISCARD FMT_INLINE auto format(format_string<T...> fmt, T&&... args)
-> basic_string<char> {
return vformat(fmt, fmt::make_format_args(args...));
}因为basic_string<char>找不到实现，怎么破？
template <typename... T, typename Char = char>
FMT_NODISCARD FMT_INLINE auto format(format_string<T...> fmt, T&&... args)
-> basic_string<Char> {
return vformat(fmt, fmt::make_format_args(args...));
}
然后这个操作就省掉了大量编译时间
结构是这样的
class WidgetContainer : IWidgetCallback
{
//
};
auto widget = std::shared_ptr<Widget>(new Widget(this));能不能换成make_shared？不能，因为是private继承
怎么破？
auto widget = std::make_shared<Widget>(
static_cast<IWidgetCallback*>(this));struct foo {
int a{};
int b{};
int c{};
};
static_assert(3 == std::size(std::meta::nonstatic_data_members_of(^foo)));deque msvc实现有坑爹的地方
| gcc | clang | msvc | |
|---|---|---|---|
| Block size | as many as fit in 512 bytes but at least 1 element | as many as fit in 4096 bytes but at least 16 elements | power of 2 that fits in 16 bytes but at least 1 element |
| Initial map size | 8 | 2 | 8 |
| Map growth | 2× | 2× | 2× |
| Map shrinkage | On request | On request | On request |
| Initial first/last | Center | Start | Start |
| Members | block** map; size_t map_size; iterator first; iterator last; |
block** map; block** first_block; block** last_block; block** end_block; size_t first; size_t size; |
block** map; size_t map_size; size_t first; size_t size; |
| Map layout | counted array | simple_deque | counted array |
| Valid range | Pair of iterators | Start and count | Start and count |
| Iterator | T* current; T* current_block_begin; T* current_block_end; block** current_block; |
T* current; block** current_block; | deque* parent; size_t index; |
| begin()/end() | Copy first and last. | Break first and first + size into block index and offset. | Break first and first + size into block index and offset. |
| Spare blocks | Aggressively pruned | Keep one on each end | Keep all |
block size太小了
- How to allocate address space with a custom alignment or in a custom address region
- How do I prevent my ATL class from participating in COM aggregation? DECLARE_NOT_AGGREGATABLE didn’t work
- The case of the vector with an impossibly large size
介绍协程并写了个co curl 有点意思，视频我也传B站了 https://www.bilibili.com/video/BV1NG411B7Fy/
代码在这里 https://github.com/hanickadot/co_curl
- fmt 10.2更新，支持duration打印 %j 还支持这么玩
#include <fmt/chrono.h>
int main() {
fmt::print("{}\n", std::chrono::days(42)); // prints "42d"
}编译期物理计算的
- nanobind 一个python binding，速度性能都不错，群友kenshin推荐
- asteria 一个脚本语言，可嵌入，长期找人，希望胖友们帮帮忙，也可以加群753302367和作者对线
- Unilang deepin的一个通用编程语言，点子有点意思，也缺人，感兴趣的可以github讨论区或者deepin论坛看一看。这里也挂着长期推荐了
- gcc-mcf 懂的都懂
https://job.toutiao.com/s/i8Tv36Jf 字节杭州虚拟机v8研发
字节的音视频团队，主要负责剪映上的音视频/非线性编辑相关工作，业务前景也比较好，目前有三个方向的岗位
- 桌面端音视频研发 https://job.toutiao.com/s/i8enPrw5
- 多端音视频引擎研发 https://job.toutiao.com/s/i8enr7Es
- C++工程基础架构研发 https://job.toutiao.com/s/i8enjTHT
base北上广深杭都可以，薪资open，有兴趣的同学可以通过链接投递
新的一年开始了，本周刊也走过了三个年头，希望大家都健康我也继续保持更新下去
如果有疑问评论最好在上面链接到评论区里评论，这样方便搜索，微信公众号有点封闭/知乎吞评论