mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Improve clarity of paragraph in the pointer guide

Browse Source 
Fixes #19067
This commit is contained in:
Steve Klabnik 2015-01-12 13:57:09 -05:00
parent b21a6da340
commit db7de969cf
1 changed files with 4 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
src/doc/trpl/pointers.md
View File

@ -721,11 +721,10 @@ fn main() {
This gives you flexibility without sacrificing performance.
You may think that this gives us terrible performance: return a value and then
immediately box it up ?! Isn't that the worst of both worlds? Rust is smarter
than that. There is no copy in this code. `main` allocates enough room for the
`box`, passes a pointer to that memory into `foo` as `x`, and then `foo` writes
the value straight into that pointer. This writes the return value directly into
the allocated box.
immediately box it up ?! Isn't this pattern the worst of both worlds? Rust is
smarter than that. There is no copy in this code. `main` allocates enough room
for the `box`, passes a pointer to that memory into `foo` as `x`, and then
`foo` writes the value straight into the `Box<T>`.
This is important enough that it bears repeating: pointers are not for
optimizing returning values from your code. Allow the caller to choose how they