Introduce common `bzero` libc implementation. (#23812)

* Introduce common `bzero` libc implementation.

* Update test name according to review

Co-authored-by: Linus Groh <mail@linusgroh.de>

* address code review

- import common implementation when musl or wasi is included
- don't use `c_builtins`, use `@memset`

* bzero calling conv to .c

* Apply review

Co-authored-by: Veikka Tuominen <git@vexu.eu>

---------

Co-authored-by: Linus Groh <mail@linusgroh.de>
Co-authored-by: Veikka Tuominen <git@vexu.eu>

1 files changed, 19 insertions, 0 deletions

diff --git a/lib/c/strings.zig b/lib/c/strings.zig
new file mode 100644
index 0000000000..30e945e7b1
--- /dev/null
+++ b/lib/c/strings.zig
@@ -0,0 +1,19 @@
+const std = @import("std");
+const common = @import("common.zig");
+
+comptime {
+    @export(&bzero, .{ .name = "bzero", .linkage = common.linkage, .visibility = common.visibility });
+}
+
+fn bzero(s: *anyopaque, n: usize) callconv(.c) void {
+    const s_cast: [*]u8 = @ptrCast(s);
+    @memset(s_cast[0..n], 0);
+}
+
+test bzero {
+    var array: [10]u8 = [_]u8{ '1', '2', '3', '4', '5', '6', '7', '8', '9', '0' };
+    var a = std.mem.zeroes([array.len]u8);
+    a[9] = '0';
+    bzero(&array[0], 9);
+    try std.testing.expect(std.mem.eql(u8, &array, &a));
+}