其中,function_name 是函数的名称,arguments 是函数的参数列表,argument_type 是参数的类型,return_type 是函数的返回值类型,value 是函数的返回值。如果函数没有返回值,可以使用 () 作为返回类型。 例如,以下是一个返回整数类型的函数: fn add(a: i32, b: i32) -> i32 { return a + b; } 以上函数的...
move_ownership(s); // s's value moves into the function... // so it' s no longer valid from this // point forward letx = 5; // x comes into scope makes_copy(x); // x would move into thefunction // It follows copy semantics since it's // primitive, so we use x afterwar...
// return value into the function // that calls it let some_string = String::from("yours"); // some_string comes into scope some_string // some_string is returned and // moves out to the calling // function } // This function takes a String and returns it fn takes_and_gives_ba...
read_a_file at .\src\main.rs:3:19 5: error_example::main at .\src\main.rs:8:16 6: core::ops::function::FnOnce::call_once at /rustc/9eb3afe9ebe9c7d2b84b71002d44f4a0edac95e0\library\core\src\ops/function.rs:250:5 note: Some details are omitted, run with `RUST_BACKTRACE=...
因此,总体而言,在rust中函数值可以被return返回,也可以是函数体中最后一个表达式的值。如果函数没有返回值,那么将返回一个()。 发散函数 除了这些以外,rust中还有发散函数,这些函数永不返回。 当用 ! 作函数返回类型的时候,表示该函数永不返回( diverge function ),特别的,这种语法往往用做会导致程序崩溃的函数:...
error[E0515]: cannot return value referencing local variable `cmd` --> src/main.rs:31:1 | 24 | codeV = re.captures(cmd.as_str()); | --- `cmd` is borrowed here ... 31 | V //Error | ^ returns a value referencing data owned by the current function ...
fnmain(){lettup:(i32,f64,u8)=(500,7.8,1);letfirstValue=x.0;letsecondValue=x.1;} 数组类型 我们同样可以在数组中存储多个值的集合。与元组不同,「数组中每一个元素都必须是相同类型」。Rust中「数组拥有固定的长度,一旦声明就再也不能随意更改大小」。
error[E0106]: missing lifetime specifier--> dangle.rs:5:16|5| fn dangle() -> &String {| ^ expected lifetime parameter|= help:thisfunction'sreturntype contains a borrowed value, but there isno valueforit to be borrowed from= help: consider giving it a 'staticlifetime ...
The value of y is: 4 函数返回值 We don’t name return values, but we do declare their type after an arrow (->). In Rust, the return value of the function is synonymous with the value of the final expression in the block of the body of a function. You can return early from a ...
let function_type = llvm::core::LLVMFunctionType(void, ptr::null_mut(), 0, 0); let function = llvm::core::LLVMAddFunction(module, b"nop\0".as_ptr() as *const _, function_type); // Create a basic block in the function and set our builder to generate ...