syscall: add DLLError.Unwrap function

Because we're expecting for future functions to be unavailable, we
should add an Unwrap() function to the DLLError struct, so that people
can test for this situation easily via:

    if errors.Is(err, syscall.ERROR_PROC_NOT_FOUND) { ... }

DLLError already was wrapping the underlying Errno error, but never got
the Go 1.13 helper method.

Fixes golang/go#42584

Change-Id: I0f32a5146946b1b37a30897ba825a56faefc792c
Reviewed-on: https://go-review.googlesource.com/c/go/+/269761
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2020-11-13 15:48:05 +01:00
parent f93ef07b11
commit f7342596da
2 changed files with 6 additions and 0 deletions

View file

@ -501,6 +501,10 @@ Do not send CLs removing the interior tags from such phrases.
<p><!-- CL 261917 -->
<a href="/pkg/syscall/#SysProcAttr"><code>SysProcAttr</code></a> on Windows has a new NoInheritHandles field that disables inheriting handles when creating a new process.
</p>
<p><!-- CL 269761, golang.org/issue/42584 -->
<a href="/pkg/syscall/#DLLError"><code>DLLError</code></a> on Windows now has an Unwrap function for unwrapping its underlying error.
</p>
</dd>
</dl><!-- syscall -->

View file

@ -20,6 +20,8 @@ type DLLError struct {
func (e *DLLError) Error() string { return e.Msg }
func (e *DLLError) Unwrap() error { return e.Err }
// Implemented in ../runtime/syscall_windows.go.
func Syscall(trap, nargs, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)