Commit 6dbfba526f

Brandon Black <bblack@wikimedia.org>
2025-09-12 14:20:08
linux: Doc and check retval for no-fail pid calls
The switch from @bitCast() to @intCast() here safety-checks Linux's assertion that these 3 calls never return errors (negative values as pid_t). getppid() can legally return 0 if the parent is in a different pid namespace, but this is not an error.
master
1 parent 04071d6
Changed files (1)
lib
std
os
linux.zig
lib/std/os/linux.zig
@@ -1839,15 +1839,18 @@ pub fn setsid() usize {
 }
 
 pub fn getpid() pid_t {
-    return @bitCast(@as(u32, @truncate(syscall0(.getpid))));
+    // Casts result to a pid_t, safety-checking >= 0, because getpid() cannot fail
+    return @intCast(@as(u32, @truncate(syscall0(.getpid))));
 }
 
 pub fn getppid() pid_t {
-    return @bitCast(@as(u32, @truncate(syscall0(.getppid))));
+    // Casts result to a pid_t, safety-checking >= 0, because getppid() cannot fail
+    return @intCast(@as(u32, @truncate(syscall0(.getppid))));
 }
 
 pub fn gettid() pid_t {
-    return @bitCast(@as(u32, @truncate(syscall0(.gettid))));
+    // Casts result to a pid_t, safety-checking >= 0, because gettid() cannot fail
+    return @intCast(@as(u32, @truncate(syscall0(.gettid))));
 }
 
 pub fn sigprocmask(flags: u32, noalias set: ?*const sigset_t, noalias oldset: ?*sigset_t) usize {