clone.2: Check for MAP_FAILED not NULL on mmap()

If mmap() fails it will return MAP_FAILED which according to the manpage
is (void *)-1 not NULL.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man2/clone.2 b/man2/clone.2
index 57a9eaba77d24667fba815e981682ad6f6d5cae5..faff2ada68a14840926f51cb69af69ab1e8e9c52 100644 (file)
--- a/man2/clone.2
+++ b/man2/clone.2
@@ -1628,7 +1628,7 @@ main(int argc, char *argv[])
 
     stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE,
                  MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, \-1, 0);
-    if (stack == NULL)
+    if (stack == MAP_FAILED)
         errExit("mmap");
 
     stackTop = stack + STACK_SIZE;  /* Assume stack grows downward */