Add documentation to std::env::args[_os]

Author: leo60228

src/libstd/env.rs

@@ -702,6 +702,11 @@ pub struct ArgsOs { inner: sys::args::Args }
 /// (such as `*` and `?`). On Windows this is not done, and such arguments are
 /// passed as-is.
 ///
+/// On glibc Linux, arguments are retrieved by placing a function in .init_array.
+/// glibc passes argc, argv, and envp to functions in .init_array, as a non-standard extension.
+/// This allows `std::env::args` to work even in a `cdylib` or `staticlib`, as it does on macOS
+/// and Windows.
+///
 /// # Panics
 ///
 /// The returned iterator will panic during iteration if any argument to the
@@ -732,6 +737,11 @@ pub fn args() -> Args {
 /// set to arbitrary text, and it may not even exist, so this property should
 /// not be relied upon for security purposes.
 ///
+/// On glibc Linux, arguments are retrieved by placing a function in .init_array.
+/// glibc passes argc, argv, and envp to functions in .init_array, as a non-standard extension.
+/// This allows `std::env::args` to work even in a `cdylib` or `staticlib`, as it does on macOS
+/// and Windows.
+///
 /// # Examples
 ///
 /// ```