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+# Random constants
+This crate provides compile time random number generation.
+This allows you to insert random constants into your code that will be auto-generated at compile time.
+
+A new value will be generated every time the file is rebuilt.
+This obviously makes the resulting binary or lib non-deterministic. (See below)
+
+# Example 
+
+```rust
+use const_random::const_random  ;
+const MY_RANDOM_NUMBER: u32 = const_random!(u32);
+```
+This works exactly as through you have called: `OsRng.gen::<u32>()` at compile time.
+So for details of the random number generation, see the `rand` crates documentation.
+
+The following types are supported: u8, i8, u16, i16, u32, i32, u64, i64, u128, i128, usize, isize and [u8; N].
+
+# Deterministic builds
+
+Sometimes it is an advantage for build systems to be deterministic. To support this `const-random` reads the environmental
+variable `CONST_RANDOM_SEED`. If this variable is set, it will be used as the seed for the random number generation.
+Setting the same seed on a build of the same code should result in identical output.
+