Compile C using GCC

GCC (shorthand for 'GNU Compiler Collection') is a collection of compilers able to compile multiple different programming languages.

This page describes how to compile C code using the GCC.

Procedure

0. Create a C source file

You will need C code to work on.

In this optional step, a file with a minimal C program is created.

Create and write a C source file called hello_world.c:

nano hello_world.c

In nano, write the C program as such:

#include <stdio.h>

int main() {
  printf("hello, world\n");
}

1. Load a GCC module

Load a recent GCC module:

module load gcc/13.2.0

Do I really need to load a module?

No, as there is a system-installed GCC.

For sake of doing reproducible research, always load a module of a specific version.

If you need the C11 or C17 standards, use these module versions or newer:

Module version	Description
gcc/4.8	Fully implemented C11 standard
gcc/8	Fully implemented C17 standard

2. Compile the source file

After saving and closing nano, compile as such:

gcc hello_world.c

This compiles the file hello_world.c using all defaults:

• default/no optimization
• the executable created is called a.out

To compiles the file hello_world.c with run-time speed optimization and creating an executable with a more sensible name, use:

gcc -O3 -o hello_world hello_world.c

• -O3: optimize for run-time speed
• -o hello_world: the executable created is called hello_world

3. Run

Run the program:

./a.out 

Output:

hello, world