Commit 6dbfba526f7b7cf1256c133d025b11409c97dda7 | zig

author	Brandon Black <bblack@wikimedia.org> 2025-09-12 07:20:08-05:00
committer	Brandon Black <bblack@wikimedia.org> 2025-09-12 07:20:08-05:00
log	6dbfba526f7b7cf1256c133d025b11409c97dda7
tree	d2b58d556ea8f61a38f87f6e98ce6556fa30fc93
parent	04071d64bb83c0600d445a2f4b2541e68a6021bf

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.

1 files changed, 6 insertions(+), 3 deletions(-)

lib
- std
  - os
    linux.zig

lib/std/os/linux.zig+6-3

 @@ -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 {