Linux cc Command with Practical Examples

Introduction

In this lab, you will learn how to use the cc command, a compiler driver for the C programming language. You will understand the purpose and syntax of the cc command, compile a simple C program, and explore various compiler flags and optimization options. The lab covers the following steps:

Understand the Purpose and Syntax of the cc Command: You will learn about the basic syntax of the cc command and the common options it supports, such as specifying the output file, compiling source files into object files, and enabling debugging or optimization.

Compile a Simple C Program Using the cc Command: You will create a simple C program and use the cc command to compile it into an executable.

Explore Compiler Flags and Optimization Options: You will learn about different compiler flags and optimization options that can be used with the cc command to control the compilation process and generate optimized code.

Linux Commands Cheat Sheet

Skills Graph

Understand the Purpose and Syntax of the cc Command

In this step, you will learn about the purpose and syntax of the cc command, which is a compiler driver for the C programming language. The cc command is used to compile C source code files into executable programs.

First, let's explore the basic syntax of the cc command:

cc [options] file(s)

The cc command takes one or more C source code files as input, along with various options to control the compilation process. The most common options include:

• -o <output>: Specifies the name of the output executable file.
• -c: Compiles the source file(s) into object file(s) without linking.
• -g: Includes debugging information in the compiled output.
• -O<n>: Specifies the optimization level, where n is a number from 0 to 3.

For example, to compile a simple C program named hello.c and create an executable named hello, you can use the following command:

cc -o hello hello.c

Example output:

This will compile the hello.c file and create an executable named hello.

Now, let's try compiling a more complex C program that includes multiple source files. Suppose you have two files, main.c and utils.c, and you want to create an executable named myapp. You can use the following command:

cc -o myapp main.c utils.c

Example output:

In this example, the cc command compiles both main.c and utils.c and links them together to create the final executable myapp.

Compile a Simple C Program Using the cc Command

In this step, you will learn how to compile a simple C program using the cc command.

First, let's create a simple C program called hello.c in the ~/project directory:

#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}

Now, let's compile this program using the cc command:

cd ~/project
cc -o hello hello.c

Example output:

The -o hello option specifies the name of the output executable file, which will be hello. The hello.c file is the input source code file.

After the compilation is complete, you can run the executable:

./hello

Example output:

Hello, World!

You should see the "Hello, World!" message printed to the console.

Explore Compiler Flags and Optimization Options

In this step, you will learn about various compiler flags and optimization options that can be used with the cc command.

Compiler flags are used to control the behavior of the compiler during the compilation process. Some common compiler flags include:

• -g: Includes debugging information in the compiled output, which is useful for debugging your program.
• -Wall: Enables all warning messages, which can help you identify potential issues in your code.
• -Werror: Treats all warnings as errors, causing the compilation to fail if any warnings are generated.

Optimization options are used to optimize the performance of your compiled program. The cc command supports several optimization levels, which are specified using the -O flag followed by a number:

• -O0: No optimization (default)
• -O1: Optimize for speed, without increasing code size
• -O2: Optimize further, potentially increasing code size
• -O3: Optimize even further, potentially increasing code size even more

For example, let's compile the hello.c program with some compiler flags and optimization options:

cd ~/project
cc -g -Wall -O2 -o hello hello.c

This will compile the hello.c program with debugging information, all warnings enabled, and optimization level 2.

You can then run the compiled program as before:

./hello

Example output:

Hello, World!

Summary

In this lab, you learned about the purpose and syntax of the cc command, which is a compiler driver for the C programming language. You explored the basic syntax of the cc command and the most common options, such as -o to specify the output file, -c to compile without linking, -g to include debugging information, and -O<n> to set the optimization level. You also learned how to compile a simple C program using the cc command, including how to compile multiple source files into a single executable.

Linux Commands Cheat Sheet