从函数返回错误
在函数签名中明确声明失败可能性。
从函数返回错误 是 CoddyKit 上的免费 Zig Academy 课时。 这是第 2 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Zig Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Zig Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Failure in the Signature
When a function can fail, say so in its return type. An error union like ParseError!u32 warns every caller up front.
fn parse(s: []const u8) ParseError!u32 {
// ...
}Return the Success Value
On the happy path you just return the payload as normal. Zig wraps that plain value into the success side of the union for you.
return 42;Return an Error Instead
To fail, return one of your errors in the same spot. The single return statement decides which side of the union you produce.
if (s.len == 0) return error.Empty;One Return, Two Outcomes
A function with an error union can return a value in one branch and an error in another. Both satisfy the declared type.
if (ok) return value;
return error.Failed;Void Plus Errors
A function that does work but yields no value can still fail. Use !void so it returns nothing on success or an error on failure.
fn save() !void {
// ...
}Errors Bubble at the Call Site
When you call a fallible function, you receive an error union too. You cannot ignore it; the compiler makes you handle it.
const n = parse(input);Capture Errors with if
An if can split the union: capture the value in the main branch and the error after else, naming each with a pipe.
if (parse(input)) |n| {
use(n);
} else |err| {
report(err);
}Name the Error Set Precisely
Listing the exact set before ! keeps your contract honest. Callers learn the full list of failures without reading the body.
fn open(p: []const u8) FileError!File {}Errors Cross Function Boundaries
An error returned deep inside your code travels outward only when each function in the chain declares it can fail too.
Make Failure Explicit
This is the heart of Zig error handling: failure is never hidden. The signature is a promise about what can go wrong.
Compiler Has Your Back
Forget to handle a returned error and the build fails. Zig refuses to let a possible failure silently slip through.
Quick Check
A function does work but returns no useful value, yet it might fail. What return type fits?
Recap
You declared fallible functions with !T, returned values or errors from one return, and saw the compiler force callers to handle them. ✅
常见问题解答
「从函数返回错误」课时是免费的吗？
是的 — 「从函数返回错误」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Zig Academy 课程的其余内容，请升级到 CoddyKit PRO。 Zig Academy 课程共包含 4 节课。
「从函数返回错误」这节课中我会学到什么？
在函数签名中明确声明失败可能性。 你通过在浏览器中直接运行的动手代码来练习 Zig Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Zig Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Zig Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 2 节课，共 4 节。
「从函数返回错误」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Zig Academy 课中编写并运行代码吗？
能。每节 Zig Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。