altstack: stack alignment and accounting tweaks

[ccan] / ccan / altstack / altstack.h

diff --git a/ccan/altstack/altstack.h b/ccan/altstack/altstack.h
index 5570e7b53031ad1716729a2596a31b90eb29ae53..4445a2a3e5563e74a1f4e6de4cb32bef725691ac 100644 (file)
--- a/ccan/altstack/altstack.h
+++ b/ccan/altstack/altstack.h
@@ -103,6 +103,20 @@ char *altstack_geterr(void);
  */
 ptrdiff_t altstack_used(void);
 
+/**
+ * altstack_max - return usable stack size
+ *
+ * Returns: max value from altstack() call
+ */
+rlim_t altstack_max(void);
+
+/**
+ * altstack_remn - return amount of stack remaining
+ *
+ * Returns: altstack_max() minus altstack_used()
+ */
+#define altstack_remn() (altstack_max() - altstack_used())
+
 /**
  * altstack_rsp_save - set initial rsp value
  *