mirror of
https://github.com/TrudeEH/web.git
synced 2025-12-06 08:23:37 +00:00
81 lines
1.7 KiB
Markdown
81 lines
1.7 KiB
Markdown
---
|
|
title: Compiling [MAKE / GCC]
|
|
description:
|
|
date: 2025-02-17T08:59:53+00:00
|
|
draft: false
|
|
tags:
|
|
- c
|
|
- programming
|
|
author: TrudeEH
|
|
showToc: true
|
|
---
|
|
|
|
|
|
Convert `C` code into machine code in 4 steps:
|
|
1. **Preprocessing** (Convert all preprocessor instructions: `#…`)
|
|
2. **Compiling** (Convert `C` code to machine code)
|
|
3. **Assembling** (Compile the necessary libraries)
|
|
4. **Linking** (Merge the compiled code with the compiled libraries)
|
|
|
|
## Libraries
|
|
|
|
Libraries are pre-written collections of code that can be reused in other programs. On **UNIX* systems, they are usually located in the `/lib/` and `/usr/include` directories.
|
|
|
|
### Math.h
|
|
|
|
For example, `math.h` is very useful to implement complex arithmetic operations.
|
|
|
|
```C
|
|
#include <math.h>
|
|
double A = sqrt(9);
|
|
double B = pow(2, 4);
|
|
int C = round(3.14);
|
|
int D = ceil(3.14);
|
|
int E = floor(3.99);
|
|
double F = fabs(-100);
|
|
double G = log(3);
|
|
double H = sin(45);
|
|
double I = cos(45);
|
|
double J = tan(45);
|
|
```
|
|
|
|
### Using Libraries
|
|
|
|
To use a library, we first have to include it in the `C` code.
|
|
|
|
```C
|
|
#include <cs50.h> // cs50.h library will be included.
|
|
```
|
|
|
|
Then, the library must be linked at compile time.
|
|
|
|
```Shell
|
|
gcc -o hello hello.c -lcs50
|
|
./hello
|
|
```
|
|
|
|
## Optimization Flags
|
|
|
|
- `-O2` Optimize for speed
|
|
- `-O3` Optimize for speed aggressively
|
|
- `-Os` Optimize for size
|
|
- `-Og` Optimize for debugging
|
|
- `-Oz` Optimize for size aggressively
|
|
|
|
## Make
|
|
|
|
`Make` Is a build automation tool that automates the process of compiling, linking and building executables.
|
|
An example `Makefile` could look like the following:
|
|
|
|
```Makefile
|
|
hello:
|
|
gcc -o hello hello.c -lcs50
|
|
clean:
|
|
rm -f hello
|
|
```
|
|
|
|
```Shell
|
|
make #Compiles hello.c
|
|
make clean #Removes the executable (hello) generated by the make command.
|
|
```
|