macro: introduce steal_fd()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/macro.h b/src/lxc/macro.h
index bd632dc1fdbf4ceecaadcb184f1aa7a9a43f66ee..61e626f2ef59b8b9081df2b1b52025aaa2c1e678 100644 (file)
--- a/src/lxc/macro.h
+++ b/src/lxc/macro.h
@@ -400,4 +400,11 @@ enum {
                _ptr_;                     \
        })
 
+#define steal_fd(fd)             \
+       ({                       \
+               int _fd_ = (fd); \
+               (fd) = -EBADF;   \
+               _fd_;            \
+       })
+
 #endif /* __LXC_MACRO_H */