comptime 매개변수와 값

Sometimes a function needs an argument the compiler can see, not just the running program. Zig lets you mark such a parameter comptime. 🧩

Write comptime before a parameter name to require that its value be known at compile-time. The caller must pass a known value.

A comptime parameter accepts only values the compiler already knows, like literals or other compile-time constants.

Pass a value that is only known at run-time into a comptime parameter and Zig reports a clear compile error.

You can also force a local expression to evaluate early. A comptime block runs during compilation and produces a constant.

A comptime var is a mutable variable that exists only during compilation. Use it to accumulate a value as compile-time code runs.

Because a comptime argument is fixed, Zig can generate a tailored version of the function for that exact value.

A function can take both kinds at once: a comptime parameter for the known part and ordinary parameters for run-time data.

Since the value is known, you can check it during compilation and stop the build if it is wrong, before the program ever runs. ✅

Work driven by a comptime parameter happens during the build. The resulting binary carries the answer with nothing left to compute.

Within the function body a comptime parameter behaves like a fixed constant, so you may use it in array sizes and other compile-time spots.

A function declares a parameter as comptime n: usize. What kind of value must the caller pass?

Mark a parameter comptime to demand a compile-time value. Zig can then validate it and specialize the function with no run-time cost. 🎯