OpenBSD GCC Compiler - Beginner Guide

OpenBSD GCC Compiler - Beginner Guide

The GCC (GNU Compiler Collection) is essential for compiling C and other programs. Here's how to install and use it on OpenBSD.

Step 1: Install GCC

OpenBSD uses the pkg_add command to install software.

pkg_add gcc - installs the GCC compiler collection

What you get: The GCC compiler, assembler, and related tools for compiling C, C++, and other languages.

After installation: Verify it worked:
gcc --version - should display version information (e.g., gcc (OpenBSD) 11.4.0)

Step 2: Your First C Program

Let's compile a simple "Hello, World!" program.

Create the source file:
vi hello.c

Press i to insert, type the following, press Esc, then type :wq and press Enter:

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

Step 3: Compiling with Warnings and Debugging

For better code quality, use these useful flags:

-Wall: Show all common warnings
-Wextra: Show extra warnings beyond Wall
-g: Include debugging information (allows using gdb debugger)

Example command:
gcc -Wall -Wextra -g hello.c -o hello

This will:
- Warn about potential issues in your code
- Add debugging symbols so you can trace through the program later
- Help you write more robust code

Step 4: Compiling C++ Programs

To compile C++ programs, use g++ (which is installed with gcc):

g++ hello.cpp -o hello

Or with warnings:
g++ -Wall -Wextra -g hello.cpp -o hello

C++ specifics: C++ has more compiler warnings than C due to its complexity.
Pay attention to warnings about deprecated functions, unused variables, etc.

Step 5: Making a Makefile

For larger projects, use a Makefile to automate compilation.

Create a Makefile:
vi Makefile

Type the following, press Esc, then type :wq and press Enter:

CC = gcc
CFLAGS = -Wall -Wextra -g
 
all: hello
 
hello: hello.c
    $(CC) $(CFLAGS) -o hello hello.c
 
clean:
    rm -f hello

Ready for more development tools? Proceed to Lesson 62: Make Build System.

Next: OpenBSD Virtual Machines - Beginner Guide

Article author: Arthur Isaev