win32: allow kill to send signal number 0

According to the man page:

   If sig is 0, then no signal is sent, but existence and permission
   checks are still performed

1 files changed, 15 insertions, 0 deletions

diff --git a/win32/process.c b/win32/process.c
index ada0d743f..9ad75f94f 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -587,6 +587,18 @@ static int terminate_process(pid_t pid, int exit_code)
         return ret;
 }
 
+static int test_process(pid_t pid, int exit_code UNUSED_PARAM)
+{
+        HANDLE process;
+
+        if (!(process=OpenProcess(PROCESS_TERMINATE, FALSE, pid))) {
+                return -1;
+        }
+
+        CloseHandle(process);
+        return 0;
+}
+
 int kill(pid_t pid, int sig)
 {
         if (sig == SIGTERM) {
@@ -595,6 +607,9 @@ int kill(pid_t pid, int sig)
         else if (sig == SIGKILL) {
                 return kill_pids(pid, 128+sig, terminate_process);
         }
+        else if (sig == 0) {
+                return kill_pids(pid, 128+sig, test_process);
+        }
 
         errno = EINVAL;
         return -1;