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> we hope will be added to the C spec one day defer seems to be making significant progress (having a passionate and motivated advocate in Meneide, and a full

> we hope will be added to the C spec one day defer seems to be making significant progress (having a passionate and motivated advocate in Meneide, and a full TS)

rwmj 2y ago
Last time I looked this was (golang-like) function scoped, not { } scoped, which means it's a bad idea. My feedback was the committee should simply standardize the existing attribute / behaviour, as that is widely used already. (EDIT: I'm wrong, see reply)
- masklinn 2y ago
  > Last time I looked this was (golang-like) function scoped, not { } scoped, which means it's a bad idea. Might have been the previous attempt from years ago, because being block scoped (unlike go) literally has its own section in https://thephd.dev/c2y-the-defer-technical-specification-its-time-go-go-go#scope-based https://thephd.dev/c2y-the-defer-technical-specification-its...
EPWN3D 2y ago
defer is nice, but I really want the cleanup attribute since it could in theory by applied to the return type of a function. In other words you could have malloc return a pointer with the cleanup attribute that automatically frees it at end of scope if it's non-NULL. (And if you want to persist the pointer just assign to a different variable and zero out the one malloc gave you.)
- masklinn 2y ago
  > In other words you could have malloc return a pointer with the cleanup attribute that automatically frees it at end of scope if it's non-NULL. That is not, as far as I know, how __attribute__((cleanup)) works. It just invokes the callback when the value goes out of scope. So you can't have malloc return an implicitly cleanup'd pointer unless malloc is a macro, in which case you can do the same with a defer block.
  - EPWN3D 2y ago
    Yeah that's why I said "in theory". You can't do that with the attribute today, but it'd be possible to add that behavior to a standardized variant of it.
milesrout 2y ago
I desperately hope it is not added, Meneide throws a tantrum like he did about his Rust conference talk, and he leaves the C committee forever. He is a malign influence that is on record as saying he dislikes C and wants it to be replaced by Rust.
WalterGillman 2y ago
Was just reading about this one the other day. Well-defined behavior and it actually solves a problem. Conceptually, I can't say it is worse than variadic functions or setjmp.

> we hope will be added to the C spec one day defer seems to be making significant progress (having a passionate and motivated advocate in Meneide, and a full TS)

rwmj 2y ago

Last time I looked this was (golang-like) function scoped, not { } scoped, which means it's a bad idea. My feedback was the committee should simply standardize the existing attribute / behaviour, as that is widely used already. (EDIT: I'm wrong, see reply)

masklinn 2y ago
> Last time I looked this was (golang-like) function scoped, not { } scoped, which means it's a bad idea. Might have been the previous attempt from years ago, because being block scoped (unlike go) literally has its own section in https://thephd.dev/c2y-the-defer-technical-specification-its-time-go-go-go#scope-based https://thephd.dev/c2y-the-defer-technical-specification-its...

EPWN3D 2y ago

defer is nice, but I really want the cleanup attribute since it could in theory by applied to the return type of a function. In other words you could have malloc return a pointer with the cleanup attribute that automatically frees it at end of scope if it's non-NULL. (And if you want to persist the pointer just assign to a different variable and zero out the one malloc gave you.)

masklinn 2y ago
> In other words you could have malloc return a pointer with the cleanup attribute that automatically frees it at end of scope if it's non-NULL. That is not, as far as I know, how __attribute__((cleanup)) works. It just invokes the callback when the value goes out of scope. So you can't have malloc return an implicitly cleanup'd pointer unless malloc is a macro, in which case you can do the same with a defer block.
- EPWN3D 2y ago
  Yeah that's why I said "in theory". You can't do that with the attribute today, but it'd be possible to add that behavior to a standardized variant of it.

milesrout 2y ago

I desperately hope it is not added, Meneide throws a tantrum like he did about his Rust conference talk, and he leaves the C committee forever. He is a malign influence that is on record as saying he dislikes C and wants it to be replaced by Rust.

WalterGillman 2y ago

Was just reading about this one the other day. Well-defined behavior and it actually solves a problem. Conceptually, I can't say it is worse than variadic functions or setjmp.