| author |  Alex Kladov <aleksey.kladov@gmail.com> 2025-06-07 18:07:53+01:00 |
| committer |  GitHub <noreply@github.com> 2025-06-07 10:07:53-07:00 |
| log | 173bc4274446a14aca2eea128b70b35b0ba18ebe |
| tree | dd8012e109095c457d045e533d16532ac80fbd95 |
| parent | aa65fd5d7ca2dda5da8454e863d196745b5a50d3 |
| signature |  Signed by PGP key B5690EEEBB952194 |
langref: undefined _is_ materialized in all safe modes (#24107)
* trailing whitespace
* langref: undefined _is_ materialized in all safe modes
I am also not super happy about the clause that immediately follows. I
_believe_ what we want to say here is that, simultaneously:
* undefined is guaranteed to be matrerialized in in all safe modes.
A Zig implementation that elides `ptr.* = undefined` in ReleaseSafe
mode would be a non-conforming implementation.
* A Zig program that relies on undefined being materialized is buggy.
But I don't think it's the time to engage this level of language-lawering!1 files changed, 2 insertions(+), 2 deletions(-)
doc/langref.html.in+2-2
| ... | ... | @@ -777,7 +777,7 @@ |
| 777 | 777 | value. Using this value would be a bug. The value will be unused, or overwritten before being used." |
| 778 | 778 | </p> |
| 779 | 779 | <p> |
| 780 | In {#link|Debug#} mode, Zig writes {#syntax#}0xaa{#endsyntax#} bytes to undefined memory. This is to catch | |
| 780 | In {#link|Debug#} and {#link|ReleaseSafe#} mode, Zig writes {#syntax#}0xaa{#endsyntax#} bytes to undefined memory. This is to catch | |
| 781 | 781 | bugs early, and to help detect use of undefined memory in a debugger. However, this behavior is only an |
| 782 | 782 | implementation feature, not a language semantic, so it is not guaranteed to be observable to code. |
| 783 | 783 | </p> |
| ... | ... | @@ -2295,7 +2295,7 @@ or |
| 2295 | 2295 | {#code|test_aligned_struct_fields.zig#} |
| 2296 | 2296 | |
| 2297 | 2297 | <p> |
| 2298 | Equating packed structs results in a comparison of the backing integer, | |
| 2298 | Equating packed structs results in a comparison of the backing integer, | |
| 2299 | 2299 | and only works for the {#syntax#}=={#endsyntax#} and {#syntax#}!={#endsyntax#} {#link|Operators#}. |
| 2300 | 2300 | </p> |
| 2301 | 2301 | {#code|test_packed_struct_equality.zig#} |