g++
===

###### tags: `III` `CPP` `Linux Tools`

## Overview
[source code -> assembly code -> object code -> machine code](https://stackoverflow.com/questions/466790/assembly-code-vs-machine-code-vs-object-code)

digraph hierarchy {

                nodesep=3.0
                bgcolor="transparent"
                node [color=Black,fontname=Courier]
                edge [style=solid, color=Black]

                preprocessor->compiler 
                compiler->assembler
                assembler->linker
}

* Preprocessing
output:

cpp hello.cpp > hello.i

g++ -E hello.cpp -o hello.i

* Compiling
output: assembly code

g++ -S hello.cpp -o hello.s 

* Assembling
output: object code (binary file) is a portion of machine code

g++ -c hello.cpp -o hello.o 

* Linking
output: complete machine code

g++ hello.cpp -o hello -L./addlib -ladd

---

## Compiling Time
Compiling time includes compilation and linking.
### Linker
- [gcc -L / -l option flags](https://www.rapidtables.com/code/linux/gcc/gcc-l.html)
- [C/C++ 靜態連結庫(.a) 與 動態連結庫(.so)](https://www.itread01.com/content/1547725521.html?fbclid=IwAR1kuHnZ6iVReRuLp6CrRfsoB3E9-DItj5kj5NWcP9y9FmgnWzx8D-RLpv8)

---

## Execution Time
Execution time includes loading and execution.
### Loader
[linux 動態裝載動態庫 ldconfig，ld.so.conf, ld.so.cache](https://www.cntofu.com/book/46/linked_and_loader/linux_dong_tai_zhuang_zaidong_tai_ku_ldd__ldconfig.md)