英文:
How to do conditional compilation with Zig?
问题
例如，我可以使用CMake为C/C++预处理器添加定义
add_definitions(-DFOO -DBAR ...)
然后我可以在条件编译中使用它们
#ifdef FOO代码 ...#endif#ifdef BAR代码 ...#endif
是否可以通过编译参数或类似的方式在Zig及其构建系统中执行相同的操作？
英文:
For example, I can add definitions for C/C++ preprocessor with CMake
add_definitions(-DFOO -DBAR ...)
and then I can use them for conditional compilation
#ifdef FOOcode ...#endif#ifdef BARcode ...#endif
Is there a way to do the same thing with Zig and its build system using compilation arguments or something like that?
答案1
得分: 3
以下是翻译好的部分：
- 创建一个名为
build.zig的单独文件，其中包含一个名为build()的函数：
const std = @import("std");pub fn build(b: *std.build.Builder) !void {const build_options = b.addOptions();// 添加命令行标志// 并设置默认值build_options.addOption(bool, "sideways", b.option(bool, "sideways", "print sideways") orelse false);// 设置可执行文件名和源代码const exe = b.addExecutable("hello", "hello.zig");exe.addOptions("build_options", build_options);// 编译并复制到 zig-out/binexe.install();}
- 在名为
hello.zig的单独文件中使用条件编译选项，使用@import("build_options")：
const std = @import("std");pub fn main() !void {const print_sideways = @import("build_options").sideways;const stdout = std.io.getStdOut().writer();if (print_sideways) {try stdout.print("Sideways Hello, {s}!\n", .{"world"});} else {try stdout.print("Regular Hello, {s}!\n", .{"world"});}}
- 使用以下命令进行编译：
zig build -Dsideways=true
- 执行
zig-out/bin/hello将输出以下内容：
Sideways Hello, world!
英文:
You can do something similar using the build system. This requires some boilerplate code to do the option handling. Following the tutorial on https://zig.news/xq/zig-build-explained-part-1-59lf for the build system and https://ziggit.dev/t/custom-build-options/138/8 for the option handling:
- Create a separate file called
build.zigthat contains a functionbuild():
const std = @import("std");pub fn build(b: *std.build.Builder) !void {const build_options = b.addOptions();// add command line flag// and set default valuebuild_options.addOption(bool, "sideways", b.option(bool, "sideways", "print sideways") orelse false);// set executable name and source codeconst exe = b.addExecutable("hello", "hello.zig");exe.addOptions("build_options", build_options);// compile and copy to zig-out/binexe.install();}
- Use the option for conditional compilation in a separate file
hello.zigusing@import("build_options"):
const std = @import("std");pub fn main() !void {const print_sideways = @import("build_options").sideways;const stdout = std.io.getStdOut().writer();if (print_sideways) {try stdout.print("Sideways Hello, {s}!\n", .{"world"});} else {try stdout.print("Regular Hello, {s}!\n", .{"world"});}}
- Compile with:
zig build -Dsideways=true
- Executing
zig-out/bin/hellogives the following output:
Sideways Hello, world!
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