Bug 3672 – [tdpl] read-modify-write (rmw) operators must be disabled for shared

shared int x; void main() { x++; } This compiles but it shouldn't. For a shared word-sized object, only reading and writing it are allowed, as well as shared and synchronized calls where applicable.

Since this is a couple of years old, can you confirm that this is still what is desired? Essentially shared variables act like rvalues except for assignment? Is the compiler expected to make reads/writes atomic or is it better disabled completely and left to atomicStore/atomicLoad etc?

CC'ing Andrei for update.

I've had a discussion with Walter in which we agreed that atomic increment should NOT be generated implicitly for shared variables. Herb Sutter also agrees that C++11 made a mistake adding the sugar to atomic<T> and recommends using named functions. Code using operands with shared data should not compile. Named functions should provide the appropriate primitives. There is no issue of code breakage because the code listed was behaving incorrectly to start with.

yebblies do you intend to write a pull for this?

(In reply to comment #4) > yebblies do you intend to write a pull for this? Not currently.

Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/7535f3dc86e9e88c4ee609dd98b5305224c3b88a Fix Issue 3672 - Read-modify-write operations should not be allowed for shared variables. https://github.com/D-Programming-Language/dmd/commit/276a69327652be8d95607cec142790baae110d0c Merge pull request #3070 from AndrejMitrovic/Fix3672 Issue 3672 - Read-modify-write operations should not be allowed for shared variables.