Commit 5464392e116b590cc9c2b662e967bc544b7d0a64 | zig

author	Alex Rønne Petersen <alex@alexrp.com> 2026-04-14 14:08:32+02:00
committer	Alex Rønne Petersen <alex@alexrp.com> 2026-04-17 12:07:57+02:00
log	5464392e116b590cc9c2b662e967bc544b7d0a64
tree	962fa999dd3b447e7aeb587ba1850aa39060fe92
parent	adb1f3efc21adad67fe2638c889178401ca602a1
signature	Signed by SSH key SHA256:7B/LJ7bpR1eX8aCXSr4mtd5M45VMPKcx9zY8e95b5QM

std.os: add APIs to determine whether Zig std requires libc for a target

This is distinct from the question of whether the target formally considers libc
to be the only stable syscall interface; for example, FreeBSD and NetBSD have
stable syscalls, but we don't yet have syscall layers for them in std.os.

3 files changed, 43 insertions(+), 14 deletions(-)

lib
- std
  - os.zig
src
- Compilation
  - Config.zig
test
- src
  - StackTrace.zig

lib/std/os.zig+41

...	...	@@ -1,4 +1,5 @@
1	1	const builtin = @import("builtin");
	2	const std = @import("std.zig");
2	3	const native_os = builtin.os.tag;
3	4
4	5	pub const linux = @import("os/linux.zig");
...	...	@@ -8,6 +9,46 @@ pub const wasi = @import("os/wasi.zig");
8	9	pub const emscripten = @import("os/emscripten.zig");
9	10	pub const windows = @import("os/windows.zig");
10	11
	12	/// Returns whether the Zig standard library requires libc in order to interface
	13	/// with the operating system on the given target.
	14	pub fn targetRequiresLibC(target: *const std.Target) bool {
	15	if (target.requiresLibC()) return true;
	16	return switch (target.os.tag) {
	17	.linux => switch (target.cpu.arch) {
	18	// https://codeberg.org/ziglang/zig/issues/30940
	19	.alpha,
	20	// https://codeberg.org/ziglang/zig/issues/30942
	21	.csky,
	22	// https://codeberg.org/ziglang/zig/issues/30943
	23	.hppa,
	24	.hppa64,
	25	// https://codeberg.org/ziglang/zig/issues/30944
	26	.microblaze,
	27	.microblazeel,
	28	// https://codeberg.org/ziglang/zig/issues/30946
	29	.sh,
	30	.sheb,
	31	// https://codeberg.org/ziglang/zig/issues/30945
	32	.sparc,
	33	// https://codeberg.org/ziglang/zig/issues/30947
	34	.xtensa,
	35	.xtensaeb,
	36	=> true,
	37	else => false,
	38	},
	39	.freebsd => true, // https://codeberg.org/ziglang/zig/issues/30981
	40	.netbsd => true, // https://codeberg.org/ziglang/zig/issues/30980
	41	.openbsd => true, // https://codeberg.org/ziglang/zig/issues/30982
	42	else => false,
	43	};
	44	}
	45
	46	/// Returns whether the Zig standard library requires libc in order to interface
	47	/// with the operating system on the current target.
	48	pub fn requiresLibC() bool {
	49	return targetRequiresLibC(&builtin.target);
	50	}
	51
11	52	test {
12	53	_ = linux;
13	54	if (native_os == .uefi) _ = uefi;

src/Compilation/Config.zig+1-10

...	...	@@ -234,19 +234,10 @@ pub fn resolve(options: Options) ResolveError!Config {
234	234	break :b true;
235	235	}
236	236	if (options.link_libc) \|x\| break :b x;
237		switch (target.os.tag) {
238		// These targets don't require libc, but we don't yet have a syscall layer for them,
239		// so we default to linking libc for now.
240		.freebsd,
241		.netbsd,
242		.openbsd,
243		=> break :b true,
244		else => {},
245		}
246	237	if (options.ensure_libc_on_non_freestanding and target.os.tag != .freestanding)
247	238	break :b true;
248	239
249		break :b target.requiresLibC();
	240	break :b std.os.targetRequiresLibC(target);
250	241	};
251	242
252	243	const link_mode = b: {

test/src/StackTrace.zig+1-4

...	...	@@ -58,10 +58,7 @@ fn addCaseTarget(
58	58	.fuchsia => false,
59	59	else => true,
60	60	};
61		const both_libc = switch (target.result.os.tag) {
62		.freebsd, .netbsd, .openbsd => false,
63		else => !target.result.requiresLibC(),
64		};
	61	const both_libc = !std.os.targetRequiresLibC(&target.result);
65	62
66	63	// See `std.debug.StackIterator.fp_usability` logic.
67	64	const fp_usability: enum { useless, unsafe, safe, ideal } = switch (target.result.cpu.arch) {