jimzah/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2024-11-26 23:22:44 +00:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

std: Allow mem.zeroes to work at comptime with extern union

Browse Source 
Fixes #10797
This commit is contained in:
Evan Haas 2022-02-05 22:18:31 -08:00 committed by Veikka Tuominen
parent 435beb4e1d
commit e382e7be2b
2 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
lib/std/mem.zig
View File

@ -309,9 +309,7 @@ pub fn zeroes(comptime T: type) T {
if (comptime meta.containerLayout(T) == .Extern) {
// The C language specification states that (global) unions
// should be zero initialized to the first named member.
var item: T = undefined;
@field(item, info.fields[0].name) = zeroes(@TypeOf(@field(item, info.fields[0].name)));
return item;
return @unionInit(T, info.fields[0].name, zeroes(info.fields[0].field_type));
}
@compileError("Can't set a " ++ @typeName(T) ++ " to zero.");
@ -417,6 +415,9 @@ test "mem.zeroes" {
var c = zeroes(C_union);
try testing.expectEqual(@as(u8, 0), c.a);
comptime var comptime_union = zeroes(C_union);
try testing.expectEqual(@as(u8, 0), comptime_union.a);
}
/// Initializes all fields of the struct with their default value, or zero values if no default value is present.

10
test/run_translated_c.zig
View File

@ -1819,4 +1819,14 @@ pub fn addCases(cases: *tests.RunTranslatedCContext) void {
\\ return 0;
\\}
, "");
cases.add("Zero-initialization of global union. Issue #10797",
\\#include <stdlib.h>
\\union U { int x; double y; };
\\union U u;
\\int main(void) {
\\ if (u.x != 0) abort();
\\ return 0;
\\}
, "");
}