Add documentation for read/write parameters

Author: tiif

src/shims/unix/fd.rs

@@ -42,6 +42,8 @@ pub trait FileDescription: std::fmt::Debug + Any {
     }
 
     /// Writes as much as possible from the given buffer, and returns the number of bytes written.
+    /// `bytes` is the buffer of bytes supplied by the caller to be written.
+    /// `dest` is where the return value should be stored.
     fn write<'tcx>(
         &self,
         _self_ref: &FileDescriptionRef,
@@ -55,6 +57,9 @@ pub trait FileDescription: std::fmt::Debug + Any {
 
     /// Reads as much as possible into the given buffer from a given offset,
     /// and returns the number of bytes read.
+    /// `ptr` is the pointer to the user supplied read buffer.
+    /// `len` indicates how many bytes the user requested.
+    /// `dest` is where the return value should be stored.
     fn pread<'tcx>(
         &self,
         _communicate_allowed: bool,
@@ -69,6 +74,8 @@ pub trait FileDescription: std::fmt::Debug + Any {
 
     /// Writes as much as possible from the given buffer starting at a given offset,
     /// and returns the number of bytes written.
+    /// `bytes` is the buffer of bytes supplied by the caller to be written.
+    /// `dest` is where the return value should be stored.
     fn pwrite<'tcx>(
         &self,
         _communicate_allowed: bool,