You have been zigged (series) : Linking static library

Blog no. 05

In this blog, we will explore how to link a zig library statically and dynamically.

First lets create a library that contains a function my_add that adds two numbers. Note that instead of pub keyword which we used in previous blog, we will be using export keyword to decorate the my_add function.

// libraries__add.zig

export fn my_add(num1: i32, num2: i32) i32 {

    return num1 + num2;

}

Build the libraries__add.zig file as a static library using the command zig build-lib -O ReleaseSafe libraries__add.zig. This will output a liblibraries__add.a file on current folder.

To use this my_add function in our main code to add numbers, we will declare the my_add function's signature in main code using extern keyword. Then at compile time, we will tell the zig compiler to link the liblibraries__add.a with our main output.

// libraries__main1.zig

const std = @import("std");



extern fn my_add(num1: i32, num2: i32) i32;



pub fn main(init: std.process.Init) !void {

    // setting up stdout writer

    var buffer: [1024]u8 = undefined;

    var file_writer = std.Io.File.Writer.init(.stdout(), init.io, &buffer);

    var stdout_writer = &file_writer.interface;



    try stdout_writer.print("{}+{}={}\n", .{ 5, 6, my_add(5, 6) });

    try stdout_writer.flush();

}

Let's build our main code and link liblibraries__add.a with the output using zig build-exe libraries__main1.zig liblibraries__add.a.

The above command will produce a libraries__main1 which when executed will print 5+6=11.

Thanks for reading. To be continued.