Raise exception when waitpid would block.

ocaml · Jan 17, 2019 · 4ef7040 · 4ef7040
1 parent f154c25
commit 4ef7040
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Showing 3 changed files with 12 additions and 0 deletions.
diff --git a/otherlibs/threads/unix.ml b/otherlibs/threads/unix.ml
@@ -184,6 +184,10 @@ type wait_flag =
     WNOHANG
   | WUNTRACED
 
+exception Waitpid_would_block
+
+let _ = Callback.register_exception "Unix.Waitpid_would_block" Waitpid_would_block
+
 let stdin = 0
 let stdout = 1
 let stderr = 2

diff --git a/otherlibs/unix/unix.ml b/otherlibs/unix/unix.ml
@@ -202,6 +202,10 @@ type wait_flag =
     WNOHANG
   | WUNTRACED
 
+exception Waitpid_would_block
+
+let _ = Callback.register_exception "Unix.Waitpid_would_block" Waitpid_would_block
+
 external execv : string -> string array -> 'a = "unix_execv"
 external execve : string -> string array -> string array -> 'a = "unix_execve"
 external execvp : string -> string array -> 'a = "unix_execvp"

diff --git a/otherlibs/unix/wait.c b/otherlibs/unix/wait.c
@@ -17,6 +17,7 @@
 
 #include <caml/mlvalues.h>
 #include <caml/alloc.h>
+#include <caml/callback.h>
 #include <caml/fail.h>
 #include <caml/memory.h>
 #include <caml/signals.h>
@@ -43,6 +44,9 @@ static value alloc_process_status(int pid, int status)
 {
   value st, res;
 
+  if (pid == 0)
+    caml_raise_constant(*caml_named_value("Unix.Wait_would_block"));
+
   if (WIFEXITED(status)) {
     st = caml_alloc_small(1, TAG_WEXITED);
     Field(st, 0) = Val_int(WEXITSTATUS(status));