# Macro serde::serde_if_integer128

source · [−]

    macro_rules! serde_if_integer128 {
        ($($tt:tt)*) => { ... };
    }

Expand description

Conditional compilation depending on whether Serde is built with support for 128-bit integers.

Data formats that wish to support Rust compiler versions older than 1.26 (or targets that lack 128-bit integers) may place the i128 / u128 methods of their Serializer and Deserializer behind this macro.

Data formats that require a minimum Rust compiler version of at least 1.26, or do not target platforms that lack 128-bit integers, do not need to bother with this macro and may assume support for 128-bit integers.

ⓘ

    use serde::{serde_if_integer128, Serializer};

    impl Serializer for MySerializer {
        type Ok = ();
        type Error = Error;

        fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error> {
            /* ... */
        }

        /* ... */

        serde_if_integer128! {
            fn serialize_i128(self, v: i128) -> Result<Self::Ok, Self::Error> {
                /* ... */
            }

            fn serialize_u128(self, v: u128) -> Result<Self::Ok, Self::Error> {
                /* ... */
            }
        }
    }

When Serde is built with support for 128-bit integers, this macro expands transparently into just the input tokens.

ⓘ

    macro_rules! serde_if_integer128 {
        ($($tt:tt)*) => {
            $($tt)*
        };
    }

When built without support for 128-bit integers, this macro expands to nothing.

ⓘ

    macro_rules! serde_if_integer128 {
        ($($tt:tt)*) => {};
    }