add example of how to link library

example/exe/.gitignore

@@ -0,0 +1,2 @@
+zig-cache/
+zig-out/

example/exe/build.zig

@@ -0,0 +1,79 @@
+const std = @import("std");
+
+// Although this function looks imperative, note that its job is to
+// declaratively construct a build graph that will be executed by an external
+// runner.
+pub fn build(b: *std.Build) void {
+    // Standard target options allows the person running `zig build` to choose
+    // what target to build for. Here we do not override the defaults, which
+    // means any target is allowed, and the default is native. Other options
+    // for restricting supported target set are available.
+    const target = b.standardTargetOptions(.{});
+
+    // Standard optimization options allow the person running `zig build` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
+
+    // Define dependencies
+    const zlib = b.dependency("zlib", .{});
+
+    const exe = b.addExecutable(.{
+        .name = "exe",
+        // In this case the main source file is merely a path, however, in more
+        // complicated build scripts, this could be a generated file.
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+    // Link z library and zlib module.
+    exe.linkLibrary(b.dependency("zlib", .{
+        .target = target,
+        .optimize = optimize,
+    }).artifact("z"));
+    exe.addModule("zlib", zlib.module("zlib"));
+
+    // This declares intent for the executable to be installed into the
+    // standard location when the user invokes the "install" step (the default
+    // step when running `zig build`).
+    b.installArtifact(exe);
+
+    // This *creates* a Run step in the build graph, to be executed when another
+    // step is evaluated that depends on it. The next line below will establish
+    // such a dependency.
+    const run_cmd = b.addRunArtifact(exe);
+
+    // By making the run step depend on the install step, it will be run from the
+    // installation directory rather than directly from within the cache directory.
+    // This is not necessary, however, if the application depends on other installed
+    // files, this ensures they will be present and in the expected location.
+    run_cmd.step.dependOn(b.getInstallStep());
+
+    // This allows the user to pass arguments to the application in the build
+    // command itself, like this: `zig build run -- arg1 arg2 etc`
+    if (b.args) |args| {
+        run_cmd.addArgs(args);
+    }
+
+    // This creates a build step. It will be visible in the `zig build --help` menu,
+    // and can be selected like this: `zig build run`
+    // This will evaluate the `run` step rather than the default, which is "install".
+    const run_step = b.step("run", "Run the app");
+    run_step.dependOn(&run_cmd.step);
+
+    // Creates a step for unit testing. This only builds the test executable
+    // but does not run it.
+    const unit_tests = b.addTest(.{
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
+
+    const run_unit_tests = b.addRunArtifact(unit_tests);
+
+    // Similar to creating the run step earlier, this exposes a `test` step to
+    // the `zig build --help` menu, providing a way for the user to request
+    // running the unit tests.
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_unit_tests.step);
+}

example/exe/build.zig.zon

@@ -0,0 +1,10 @@
+.{
+    .name = "exe",
+    .version = "0.1.0",
+    .dependencies = .{
+        .zlib = .{
+            .url = "https://github.com/ianic/zig-zlib/archive/9186b0f5fdfd6c29cd04f7ada7b0113fe1f63611.tar.gz",
+            .hash = "122001cc3da638f9315f08fb51fe5aace68c254b59bcac3457e20d746565bad7fe04",
+        },
+    },
+}

example/exe/src/main.zig

@@ -0,0 +1,29 @@
+const std = @import("std");
+const zlib = @import("zlib");
+
+pub fn main() !void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+
+    const input = "Hello";
+    var cmp = try zlib.Compressor.init(allocator, .{ .header = .none });
+    defer cmp.deinit();
+    const compressed = try cmp.compressAllAlloc(input);
+    defer allocator.free(compressed);
+
+    var dcp = try zlib.Decompressor.init(allocator, .{ .header = .none });
+    defer dcp.deinit();
+    const decompressed = try dcp.decompressAllAlloc(compressed);
+    defer allocator.free(decompressed);
+
+    try std.testing.expectEqualSlices(u8, input, decompressed);
+    std.debug.print("decompressed: {s}\n", .{decompressed});
+}
+
+test "simple test" {
+    var list = std.ArrayList(i32).init(std.testing.allocator);
+    defer list.deinit(); // try commenting this out and see if zig detects the memory leak!
+    try list.append(42);
+    try std.testing.expectEqual(@as(i32, 42), list.pop());
+}