Rico贾若童的博客

C++ Profiling and Speed Ups

gprof, perf, CMake Release and Debug BoilerPlate, CMake Settings

Gprof GNU gprof provides CPU execution times (not wall time, so sleep is not accounted for) of functions and their subfunctions in percentage. Gprof outputs data in a text-based format, which can ...

Posted by Rico's Nerd Cluster on May 24, 2023

C++ - GTest

GTest For ROS

Concepts Google Test (a.k.a GTest) is an open source unit testing structure. From the official website Test Suite vs Test Case: A test suite contains one or many tests. You should group your t...

Posted by Rico's Nerd Cluster on May 21, 2023

ROS - GDB

GDB for ROS, Core Dump

Introduction GDB is EXTREMELY handy. I used to doing a lot of print statements, but now I use GDB a lot. The reason is simple: I can check multiple things at once without recompiling everytime, es...

Posted by Rico's Nerd Cluster on May 20, 2023

C++ - [Compilation 5] Compilation Speed Ups

Header-only Library Hurts Compilation Time My halo library takes ~2-3min to compile. I have ~20 executables, each executable does target_include_files(70_header_files). Why It’s Slow Every tr...

Posted by Rico's Nerd Cluster on May 13, 2023

C++ - [Compilation 4] Name Mangling

nm

Motivating Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 void foo(){ const size_t N = 100'000'000; std::vector<int> v(N); // fill v with 1,2,3,... std::...

Posted by Rico's Nerd Cluster on May 7, 2023

C++ - [Compilation 3] Linkage

In C++, Linkage is Either External Or Internal

Linkage In C and C++, linkage determines the accessibility of functions & variables defined in one source file in other different translation units (i.e., different source files). There are t...

Posted by Rico's Nerd Cluster on May 7, 2023

C++ - [Compilation 2] Compiler Directives

Macros, Pragmas, Attributes

Introduction Compiler directives are instructions that are not part of C++ / C standards, but tell the compiler how to compile the code. They starts with # (pronounced as “hash”), and are handled ...

Posted by Rico's Nerd Cluster on May 4, 2023

C++ - ABI Compatibility

ABI Compatibility: Introduction and Motivating Example ABI stands for Application Binary Interface. Two versions of the same library might be API-Compatible (you can recompile your code), but they...

Posted by Rico's Nerd Cluster on April 9, 2023

C++ - Pimpl Idiom

Minimal Structure 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 // header // Widget.hpp #pragma once #include <memory> class Widget { public: Widget(); ~Widget(); void doSomething...

Posted by Rico's Nerd Cluster on March 18, 2023

C++ - Smart Pointers

unique_ptr, shared_ptr

Common Operations Reset: std::unique_ptr::reset() and std::shared_ptr::reset unique_ptr::reset() is basically basically delete ptr; ptr = nullptr std::shared_ptr::reset() can be a bit slower...