Add SCML for waitid syscall

book/src/kernel/linux-compatibility/README.md

@@ -267,7 +267,7 @@ which are summarized in the table below.
 | 244     | mq_notify              | ❌             | N/A |
 | 245     | mq_getsetattr          | ❌             | N/A |
 | 246     | kexec_load             | ❌             | N/A |
-| 247     | waitid                 | ✅             | ❓ |
+| 247     | waitid                 | ✅             | [⚠️](syscall-flag-coverage/process-and-thread-management/#waitid) |
 | 248     | add_key                | ❌             | N/A |
 | 249     | request_key            | ❌             | N/A |
 | 250     | keyctl                 | ❌             | N/A |

book/src/kernel/linux-compatibility/syscall-flag-coverage/process-and-thread-management/README.md

@@ -66,3 +66,17 @@ Unsupported policies or flags:
 
 For more information,
 see [the man page](https://man7.org/linux/man-pages/man2/sched_setscheduler.2.html).
+
+### `waitid`
+
+Supported functionality in SCML:
+
+```c
+{{#include waitid.scml}}
+```
+
+Ignored options:
+* `WEXITED`
+
+For more information,
+see [the man page](https://man7.org/linux/man-pages/man2/waitid.2.html).

book/src/kernel/linux-compatibility/syscall-flag-coverage/process-and-thread-management/waitid.scml

@@ -0,0 +1,7 @@
+// Wait for a child process to change state
+waitid(
+    which = P_PID | P_PIDFD | P_PGID | P_ALL,
+    pid, infop,
+    options = WNOHANG | WSTOPPED | WCONTINUED | WNOWAIT,
+    ru
+);