Avoid gcc warning.

[adu.git] / adu.h

diff --git a/adu.h b/adu.h
index 42b9471ee251e0ccf28ffd185628bfdd3d315634..83c3c664daa2fcfc4acea3e40e225834baef4638 100644 (file)
--- a/adu.h
+++ b/adu.h
@@ -85,6 +85,21 @@
 #endif
 /** \endcond */
 
+/**
+ * Wrapper for isspace.
+ * NetBSD needs this.
+ */
+/*
+ * The values should be cast to an unsigned char first, then to int.
+ * Why? Because the isdigit (as do all other is/to functions/macros)
+ * expect a number from 0 upto and including 255 as their (int) argument.
+ * Because char is signed on most systems, casting it to int immediately
+ * gives the functions an argument between -128 and 127 (inclusive),
+ * which they will use as an array index, and which will thus fail
+ * horribly for characters which have their most significant bit set.
+ */
+#define adu_isspace(c) isspace((int)(unsigned char)(c))
+
 /**
  * Write a log message to a dynamically allocated string.
  *