1998-07-22 Ben Elliston <bje@cygnus.com>

	* pthread.h (pthread_atfork): Add function prototype.

	* fork.c (pthread_atfork): Preliminary implementation.
	(_pthread_fork): Likewise.

1 files changed, 64 insertions, 0 deletions

diff --git a/fork.c b/fork.c
new file mode 100644
index 0000000..0b27558
--- /dev/null
+++ b/fork.c
@@ -0,0 +1,64 @@
+/*
+ * fork.c
+ *
+ * Description:
+ * Implementation of fork() for POSIX threads.
+ */
+
+int
+pthread_atfork(void (*prepare)(void),
+	       void (*parent)(void),
+	       void (*child)(void))
+{
+  /* Push handlers (unless NULL) onto their respective stacks. */
+
+  if (prepare != NULL)
+    {
+      /* Push prepare. */
+      /* If push fails, return ENOMEM. */
+    }
+
+  if (parent != NULL)
+    {
+      /* Push parent. */
+      /* If push fails, return ENOMEM. */
+    }
+
+  if (child != NULL)
+    {
+      /* Push child. */
+      /* If push fails, return ENOMEM. */
+    }
+
+  /* Everything is okay. */
+  return 0;
+}
+
+/* It looks like the GNU linker is capable of selecting this version of
+   fork() over a version provided in more primitive libraries further down
+   the linker command line. */
+
+pid_t
+fork()
+{
+  pid_t pid;
+
+  /* Pop prepare handlers here. */
+
+  /* Now call Cygwin32's fork(). */
+
+  if ((pid = _fork()) > 0)
+    {
+      /* Pop parent handlers. */
+      return pid;
+    }
+  else
+    {
+      /* Pop child handlers. */
+      /* Terminate all threads except pthread_self() using
+	 pthread_cancel(). */
+      return 0;
+    }
+
+  /* Not reached. */
+}