zig

commit ecb9ddf2672fa1f067c240d914a5baf3a4d2d8a4 (tree)
parent 9b415761dd66904aef363e387b4501f3ddd0bf76
Author: Brandon Black <bblack@wikimedia.org>
Date:   Wed, 28 Jan 2026 16:54:04 -0600

Threaded.sleepPosix: fix libc error handling

Confusingly, the POSIX spec for clock_nanosleep() says it returns
*positive* error values directly and does not touch `errno`. Not
detecting EINTR properly here was breaking the cancellation of
threads blocked in this call when linking libc.

Diffstat:
M
lib/std/Io/Threaded.zig
 | 
6
++++--

1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/lib/std/Io/Threaded.zig b/lib/std/Io/Threaded.zig
@@ -10083,10 +10083,12 @@ fn sleepPosix(timeout: Io.Timeout) Io.SleepError!void {
     var timespec: posix.timespec = timestampToPosix(deadline_nanoseconds);
     const syscall: Syscall = try .start();
     while (true) {
-        switch (posix.errno(posix.system.clock_nanosleep(clock_id, .{ .ABSTIME = switch (timeout) {
+        const rc = posix.system.clock_nanosleep(clock_id, .{ .ABSTIME = switch (timeout) {
             .none, .duration => false,
             .deadline => true,
-        } }, &timespec, &timespec))) {
+        } }, &timespec, &timespec);
+        // POSIX-standard libc clock_nanosleep() returns *positive* errno values directly
+        switch (if (builtin.link_libc) @as(posix.E, @enumFromInt(rc)) else posix.errno(rc)) {
             .SUCCESS => {
                 syscall.finish();
                 return;