Tracking issue for std::dynamic_lib #27810

alexcrichton · 2015-08-13T17:11:54Z

This is a tracking issue for the unstable dynamic_lib feature of the standard library. This module should probably just be made private to the standard library and the compiler rather than being exported for now. A future RFC could decide whether it should be a module in the standard library or not.

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nagisa · 2015-08-13T17:23:39Z

dlopen bindings in some form is a very useful thing to have, but I personally care little whether it is stabilised in stdlib or moved out into an external crate.

alexcrichton · 2015-08-13T17:27:06Z

Yeah if we remove from the standard library I'd definitely at least want an external crate with this functionality. That being said the standard library does indeed use this as an implementation detail for various aspects, so that may be a good indicator that it should be in libstd to begin with.

nagisa · 2015-08-14T20:17:50Z

I so far found a several problems with the API exposed currently:

Some of the exposed methods are not cross-platform or might not do what’s intended. Most notably the methods dealing with search pathes… On Windows it doesn’t use AddDllDirectory/SetDllDirectory and manipulates environment instead. Man pages claim that on unix LD_LIBRARY_PATH may not be accounted for in some reasons and as far as I interpret the text (didn’t test, though) only the value of the variable as it was during process initialisation is used.

dlsym returns *mut void, and GetProcAddress returns FARPROC. *mut void is a regular pointer and FARPROC is a function pointer. While POSIX-compiliance requires *mut T and function pointers be interchangeable, I couldn’t find anything of a sort for Windows. That is, on POSIX-compiliant systems you can dlsym functions and statics and whatnot, while on Windows only function pointers can be safely retrieved.

Publicly exposed create_path and envvar methods make no sense. Instead of &Path, P: AsRef<Path> should be taken and symbols are not utf-8 therefore &str in symbol is a no-go.

Finally, I feel like there should be a simple way to prevent using symbols after the library is dropped, by e.g. returning &'library mut T? I’m experimenting with that.

durka · 2015-08-31T17:01:15Z

FWIW there is a crate which is just a copy of the unstable API from libstd, and if the crates.io download count is to be believed it has rather widespread usage.

sfackler · 2015-09-17T05:45:39Z

It seems like we should probably be deprecating and removing the in-tree version of this. The API's pretty bad right now and improvements should probably be prototyped out of tree.

nagisa · 2015-09-17T06:51:27Z

I’m experimenting with various options on my free time: libloading

alexcrichton · 2015-09-24T15:30:52Z

This issue is now entering its cycle-long FCP for deprecation in 1.5

diwic · 2015-09-25T07:27:51Z

There is also the shared_library crate.

Would be good to offer an recommended alternative in the compiler message.

durka · 2015-09-25T15:06:38Z

Really seems like a systems language should have this in std. (I realize we
need to experiment to find the right API.)
On Sep 25, 2015 3:28 AM, "diwic" notifications@github.com wrote:

There is also the shared_library https://crates.io/crates/shared_library
crate.

Would be good to offer an recommended alternative in the compiler message.

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#27810 (comment).

retep998 · 2015-10-20T22:39:59Z

While POSIX-compiliance requires *mut T and function pointers be interchangeable, I couldn’t find anything of a sort for Windows. That is, on POSIX-compiliant systems you can dlsym functions and statics and whatnot, while on Windows only function pointers can be safely retrieved.

For Win32 and Win64, all normal pointers are interchangeable, so both function and data pointers can be retrieved fine. Far and near only mattered in the times of Win16.

alexcrichton · 2015-10-22T00:10:28Z

The libs team discussed this today and the decision was to deprecate.

This commit stabilizes and deprecates library APIs whose FCP has closed in the last cycle, specifically: Stabilized APIs: * `fs::canonicalize` * `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists, is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait. * `Formatter::fill` * `Formatter::width` * `Formatter::precision` * `Formatter::sign_plus` * `Formatter::sign_minus` * `Formatter::alternate` * `Formatter::sign_aware_zero_pad` * `string::ParseError` * `Utf8Error::valid_up_to` * `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}` * `<[T]>::split_{first,last}{,_mut}` * `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated but will be once 1.5 is released. * `str::{R,}MatchIndices` * `str::{r,}match_indices` * `char::from_u32_unchecked` * `VecDeque::insert` * `VecDeque::shrink_to_fit` * `VecDeque::as_slices` * `VecDeque::as_mut_slices` * `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`) * `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`) * `Vec::resize` * `str::slice_mut_unchecked` * `FileTypeExt` * `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}` * `BinaryHeap::from` - `from_vec` deprecated in favor of this * `BinaryHeap::into_vec` - plus a `Into` impl * `BinaryHeap::into_sorted_vec` Deprecated APIs * `slice::ref_slice` * `slice::mut_ref_slice` * `iter::{range_inclusive, RangeInclusive}` * `std::dynamic_lib` Closes rust-lang#27706 Closes rust-lang#27725 cc rust-lang#27726 (align not stabilized yet) Closes rust-lang#27734 Closes rust-lang#27737 Closes rust-lang#27742 Closes rust-lang#27743 Closes rust-lang#27772 Closes rust-lang#27774 Closes rust-lang#27777 Closes rust-lang#27781 cc rust-lang#27788 (a few remaining methods though) Closes rust-lang#27790 Closes rust-lang#27793 Closes rust-lang#27796 Closes rust-lang#27810 cc rust-lang#28147 (not all parts stabilized)

This commit stabilizes and deprecates library APIs whose FCP has closed in the last cycle, specifically: Stabilized APIs: * `fs::canonicalize` * `Path::{metadata, symlink_metadata, canonicalize, read_link, read_dir, exists, is_file, is_dir}` - all moved to inherent methods from the `PathExt` trait. * `Formatter::fill` * `Formatter::width` * `Formatter::precision` * `Formatter::sign_plus` * `Formatter::sign_minus` * `Formatter::alternate` * `Formatter::sign_aware_zero_pad` * `string::ParseError` * `Utf8Error::valid_up_to` * `Iterator::{cmp, partial_cmp, eq, ne, lt, le, gt, ge}` * `<[T]>::split_{first,last}{,_mut}` * `Condvar::wait_timeout` - note that `wait_timeout_ms` is not yet deprecated but will be once 1.5 is released. * `str::{R,}MatchIndices` * `str::{r,}match_indices` * `char::from_u32_unchecked` * `VecDeque::insert` * `VecDeque::shrink_to_fit` * `VecDeque::as_slices` * `VecDeque::as_mut_slices` * `VecDeque::swap_remove_front` - (renamed from `swap_front_remove`) * `VecDeque::swap_remove_back` - (renamed from `swap_back_remove`) * `Vec::resize` * `str::slice_mut_unchecked` * `FileTypeExt` * `FileTypeExt::{is_block_device, is_char_device, is_fifo, is_socket}` * `BinaryHeap::from` - `from_vec` deprecated in favor of this * `BinaryHeap::into_vec` - plus a `Into` impl * `BinaryHeap::into_sorted_vec` Deprecated APIs * `slice::ref_slice` * `slice::mut_ref_slice` * `iter::{range_inclusive, RangeInclusive}` * `std::dynamic_lib` Closes #27706 Closes #27725 cc #27726 (align not stabilized yet) Closes #27734 Closes #27737 Closes #27742 Closes #27743 Closes #27772 Closes #27774 Closes #27777 Closes #27781 cc #27788 (a few remaining methods though) Closes #27790 Closes #27793 Closes #27796 Closes #27810 cc #28147 (not all parts stabilized)

perlun · 2019-01-21T19:29:53Z

For reference - std::dynamic_lib seems to be officially gone now; at least, its documentation which was originally available here is gone. Just for the sake of completeness, does anyone know in which Rust version it was dropped? (Or if it isn't, where are the docs now?)

sfackler · 2019-01-21T19:32:59Z

It was deprecated in 1.5.

sfackler added the I-nominated label Sep 17, 2015

alexcrichton added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed I-nominated labels Sep 24, 2015

steveklabnik added this to the 1.5 milestone Oct 1, 2015

Manishearth removed the E-easy Call for participation: Easy difficulty. Experience needed to fix: Not much. Good first issue. label Oct 2, 2015

alexcrichton mentioned this issue Oct 23, 2015

std: Stabilize library APIs for 1.5 #29254

Merged

bors closed this as completed in #29254 Oct 25, 2015

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Tracking issue for std::dynamic_lib #27810

Tracking issue for std::dynamic_lib #27810

alexcrichton commented Aug 13, 2015

nagisa commented Aug 13, 2015

alexcrichton commented Aug 13, 2015

nagisa commented Aug 14, 2015

durka commented Aug 31, 2015

sfackler commented Sep 17, 2015

nagisa commented Sep 17, 2015

alexcrichton commented Sep 24, 2015

diwic commented Sep 25, 2015

durka commented Sep 25, 2015

retep998 commented Oct 20, 2015

alexcrichton commented Oct 22, 2015

perlun commented Jan 21, 2019

sfackler commented Jan 21, 2019

Tracking issue for std::dynamic_lib #27810

Tracking issue for std::dynamic_lib #27810

Comments

alexcrichton commented Aug 13, 2015

nagisa commented Aug 13, 2015

alexcrichton commented Aug 13, 2015

nagisa commented Aug 14, 2015

durka commented Aug 31, 2015

sfackler commented Sep 17, 2015

nagisa commented Sep 17, 2015

alexcrichton commented Sep 24, 2015

diwic commented Sep 25, 2015

durka commented Sep 25, 2015

retep998 commented Oct 20, 2015

alexcrichton commented Oct 22, 2015

perlun commented Jan 21, 2019

sfackler commented Jan 21, 2019