Add a clarifying comment.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14426

diff --git a/coregrind/m_mallocfree.c b/coregrind/m_mallocfree.c
index 5e8e45921085e20c2770b11c93ef4b958ea71bec..043069b36d1a0b59da102cee346e264faa4537ff 100644 (file)
--- a/coregrind/m_mallocfree.c
+++ b/coregrind/m_mallocfree.c
@@ -1673,6 +1673,9 @@ void add_one_block_to_stats (Arena* a, SizeT loaned)
    a->stats__tot_bytes  += (ULong)loaned;
 }
 
+/* Allocate a piece of memory of req_pszB bytes on the given arena.
+   The function may return NULL if (and only if) aid == VG_AR_CLIENT.
+   Otherwise, the function returns a non-NULL value. */
 void* VG_(arena_malloc) ( ArenaId aid, const HChar* cc, SizeT req_pszB )
 {
    SizeT       req_bszB, frag_bszB, b_bszB;