util: document why we have alloca_align()

[elogind.git] / src / shared / util.h

diff --git a/src/shared/util.h b/src/shared/util.h
index a15ce95a6564de73dcaac200e769e3374c4b0a10..9a878ca1ac13a00a02a0dffe7b198b59160d4dd8 100644 (file)
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -883,6 +883,7 @@ int unlink_noerrno(const char *path);
                 (void *) memset(_new_, 0, _len_);       \
         })
 
+/* It's not clear what alignment glibc/gcc alloca() guarantee, hence provide a guaranteed safe version */
 #define alloca_align(size, align)                                       \
         ({                                                              \
                 void *_ptr_;                                            \