Raising exceptions halfway through a memory allocation is undefined
behavior since exceptions themselves require multiple allocations and
the allocator functions are not reentrant.
It is of course also expensive performance-wise to introduce lots of
exception-raising code everywhere since it breaks many optimisations and
bloats the code.
Finally, performing pointer arithmetic with signed integers is incorrect
for example on on a 32-bit systems that allows up to 3gb of address
space for applications (large address extensions) and unnecessary
elsewhere - broadly, stuff inside the memory allocator is generated by
the compiler or controlled by the standard library meaning that
applications should not be forced to pay this price.
If we wanted to check for overflow, the right way would be in the
initial allocation location where both the size and count of objects is
known.
The code is updated to use the same arithmetic operator style as for
refc with unchecked operations rather than disabling overflow checking
wholesale in the allocator module - there are reasons for both, but
going with the existing flow seems like an easier place to start.
Reverts nim-lang/Nim#25090
It seems to cause problems for C++ and i686
```
2025-08-08T02:37:55.5976232Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pstd@sprivate@ssyslocks.nim.c.o:@pstd@sprivate@ssyslocks.nim.c:(.text+0x29): undefined reference to `SleepConditionVariableCS'
2025-08-08T02:37:55.5978066Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pthreadpool.nim.c.o:@pthreadpool.nim.c:(.text+0x26): undefined reference to `InitializeConditionVariable'
2025-08-08T02:37:55.5980101Z c:/a/nightlies/nightlies/external/mingw32/bin/../lib/gcc/i686-w64-mingw32/11.1.0/../../../../i686-w64-mingw32/bin/ld.exe: C:\Users\runneradmin\nimcache\manual_experimental_snippet_106_d\@pthreadpool.nim.c.o:@pthreadpool.nim.c:(.text+0x116): undefined reference to `WakeConditionVariable'
2025-08-08T02:37:55.5981093Z collect2.exe: error: ld returned 1 exit status
2025-08-08T02:37:55.5988564Z Error: execution of an external program failed: 'gcc.exe -o
```
On windows, `HANDLE` type values are converted to `syncio.FileHandle` in
`lib/std/syncio.nim`, `lib/pure/memfiles.nim` and `lib/pure/osproc.nim`.
`HANDLE` type is `void *` on Windows and its size is larger then `cint`.
https://learn.microsoft.com/en-us/windows/win32/winprog/windows-data-types
This PR change `syncio.FileHandle` type so that converting `HANDLE` type
to `syncio.FileHandle` doesn't lose bits.
We can keep `FileHandle` unchanged and change some of parameter/return
type from `FileHandle` to an type same size to `HANDLE`, but it is
breaking change.
Essentially this PR removes the `{.error.}` pragmas littered around in
the OS module and submodules which prevents them from being imported if
the target OS is not supported. This made it impossible to use certain
supported features of the OS module in macros from a supported host OS.
Instead of the `{.error.}` pragmas the `oscommon` module now has a
constant `supportedSystem` which is false in the cases where the
`{.error.}` pragmas where generated. All procedures which can't be run
by macros is also not declared when `supportedSystem` is false.
It would be possible to create dummy versions of the omitted functions
with an `{.error.}` pragma that would trigger upon their use, but this
is currently not done.
This properly fixes#19414
fixes#24559
The strformat macros have the problem that they don't capture symbols,
so don't use them in the generic `fromJson` proc here. Also `fromJson`
refers to `jsonTo` before it is declared which doesn't capture it, so
it's now forward declared.
split from #24425
The added test did not work previously. The result of `getTypeImpl` is
the uninstantiated AST of the original type symbol, and the macro
attempts to use this type for the result. To fix the issue, the provided
`typedesc` argument is used instead.
refs #6978, refs #6752, refs #21613, refs #24234
The `jsNoInt64`, `whenHasBigInt64`, `whenJsNoBigInt64` templates are
replaced with bool constants to use with `when`. Weird that I didn't do
this in the first place.
The `whenJsNoBigInt64` template was also slightly misleading. The first
branch was compiled for both no bigint64 on JS as well as on C/C++. It
seems only `trandom` depended on this by mistake.
The workaround for #6752 added in #6978 to `times` is also removed with
`--jsbigint64:on`, but #24233 was also encountered with this, so this PR
depends on #24234.
closes https://github.com/nim-lang/RFCs/issues/554
Adds a symmetric difference operation to the language bitset type. This
maps to a simple `xor` operation on the backend and thus is likely
faster than the current alternatives, namely `(a - b) + (b - a)` or `a +
b - a * b`. The compiler VM implementation of bitsets already
implemented this via `symdiffSets` but it was never used.
The standalone binary operation is added to `setutils`, named
`symmetricDifference` in line with [hash
sets](https://nim-lang.org/docs/sets.html#symmetricDifference%2CHashSet%5BA%5D%2CHashSet%5BA%5D).
An operator version `-+-` and an in-place version like `toggle` as
described in the RFC are also added, implemented as trivial sugar.
Corrects a slicing mistake in the `std/varints` implementation which
caused it to fail when writing large numbers into buffers smaller than
10..13-bytes, now 9-byte buffers are sufficient as the documentation
states.
fixes#10440, fixes#13871, fixes#14665, fixes#19672, fixes#23677
The false positive in #23677 was caused by behavior in
`implicitlyDiscardable` where only the last node of `if`/`case`/`try`
etc expressions were considered, as in the final node of the final
branch (in this case `else`). To fix this we use the same iteration in
`implicitlyDiscardable` that we use in `endsInNoReturn`, with the
difference that for an `if`/`case`/`try` statement to be implicitly
discardable, all of its branches must be implicitly discardable.
`noreturn` calls are also considered implicitly discardable for this
reason, otherwise stuff like `if true: discardableCall() else: error()`
doesn't compile.
However `endsInNoReturn` also had bugs, one where `finally` was
considered in noreturn checking when it shouldn't, another where only
`nkIfStmt` was checked and not `nkIfExpr`, and the node given for the
error message was bad. So `endsInNoReturn` now skips over
`skipForDiscardable` which no longer contains
`nkIfStmt`/`nkCaseStmt`/`nkTryStmt`, stores the first encountered
returning node in a var parameter for the error message, and handles
`finally` and `nkIfExpr`.
Fixing #23677 already broke a line in `syncio` so some package code
might be affected.
Because `isGitRepo()` call requires `/bin/sh` it will always fail when
building Nim in a Nix build sandbox, and the check doesn't even make
sense if Nix already provides Nimble source code.
Since for Nimble `allowBundled` is set to `true` this effectlvely does
not change behavior for normal builds, but does avoid ugly hacks when
building in Nix which lacks `/bin/sh` and fails to call `git`.
Reference:
*
https://github.com/status-im/nimbus-eth2/pull/6180#discussion_r1570237858
Signed-off-by: Jakub Sokołowski <jakub@status.im>
Added a second example inside the `typedthreads` file.
Also, add a more detailed introduction. When Nim is one's first
programming language, a short explanation of what a thread is might not
hurt.
For reference, the thread documentation of other languages looks like
this:
- https://en.cppreference.com/w/cpp/thread/thread
- https://doc.rust-lang.org/std/thread/
The documentation of a module is the first place one will look when
using a standard library feature, so I think it is important to have a
few usable examples for the main modules.
This is the example added
```nim
import locks
var l: Lock
proc threadFunc(obj: ptr seq[int]) {.thread.} =
withLock l:
for i in 0..<100:
obj[].add(obj[].len * obj[].len)
proc threadHandler() =
var thr: array[0..4, Thread[ptr seq[int]]]
var s = newSeq[int]()
for i in 0..high(thr):
createThread(thr[i], threadFunc, s.addr)
joinThreads(thr)
echo s
initLock(l)
threadHandler()
deinitLock(l)
```
Sharing memory between threads is very very common, so I think having an
example showcasing this is crucial.
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
## Reprodution
if on Windows:
```Nim
when defined(windows):
var file: File
let succ = file.open(<aFileHandle>)
```
then `succ` will be false.
If tested, it can be found to fail with errno `22` and message: `Invalid
argument`
## Problem
After some investigations and tests,
I found it's due to the `mode` argument for `fdopen`.
Currently `NoInheritFlag`(`'N'` in Windows) is added to `mode` arg
passed to `_fdopen`, but if referring to
[Windows `_fdopen`
doc](https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/fdopen-wfdopen?view=msvc-170),
you'll find there is no `'N'` describled. That's `'N'` is not accepted
by `_fdopen`.
Therefore, the demo above will fail.
## In Addition
To begin with, technologically speaking, when opening with a
`fileHandle`(or called `fd`), there is no concept of fd-inheritable as
`fd` is opened already.
In POSIX, `NoInheritFlag` is defined as `e`.
It's pointed out in [POSIX `open`
man-doc](https://www.man7.org/linux/man-pages/man3/fopen.3.html) that
`e` in mode is ignored for fdopen(),
which means `e` for `fdopen()` is not wanted, just allowed.
Therefore, better to also not pass `e` to `fdopen`
---
In all, that's this PR.
When target is nodejs,
`isAbsolute` used to only check in the POSIX flavor,
i.e. for js backend on Windows,
```nim
isAbsolute(r"C:\Windows") == false
```
This fixes it.
In doc, there are 4 references for `getAppFilename`
`getAppFilename` is still in `os`, but the references refer it as if
it's in the current module `cmdline`
why ?
- We already have an emit that does the same thing
- The name asm itself is a bit confusing, you might think it's an alias
for asm.js or something else.
- The asm keyword is used differently on different compiler targets (it
makes it inexpressive).
- Does anyone (other than some compiler libraries) use asm instead of
emit ? If yes, it's a bit strange to use asm somewhere and emit
somewhere. By making the asm keyword for js target deprecated, there
would be even less use of the asm keyword for js target, reducing the
amount of confusion.
- New users might accidentally use a non-universal approach via the asm
keyword instead of emit, and then when they learn about asm, try to
figure out what the differences are.
see https://forum.nim-lang.org/t/10821
---------
Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
Per manual, `panics:on` affects _only_ `Defect`:s - thus `sysFatal`
should not redirect any other exceptions.
Also, when `sysFatal` is used in `nimPanics` mode, it should use regular
exception handling pipeline to ensure exception hooks are called
consistently for all raised defects.
At least on modern Nim `tempfiles` is not usable if the user has
https://github.com/oprypin/nim-random installed, because the compiler
picks the nimble path over the stdlib path (apparently).
