AST-2009-005

git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.0@211551 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 11 insertions, 0 deletions

diff --git a/doc/CODING-GUIDELINES b/doc/CODING-GUIDELINES
index 3050a507c..1a7f28c79 100644
--- a/doc/CODING-GUIDELINES
+++ b/doc/CODING-GUIDELINES
@@ -370,6 +370,17 @@ you wish to put into it (even if you did not allocate the buffer yourself),
 use a direct strcpy(), as it can be inlined and optimized to simple
 processor operations, unlike ast_copy_string().
 
+* String conversions
+--------------------
+
+When converting from strings to integers or floats, use the sscanf function
+in preference to the atoi and atof family of functions, as sscanf detects
+errors.  Always check the return value of sscanf to verify that your numeric
+variables successfully scanned before using them.  Also, to avoid a potential
+libc bug, always specify a maximum width for each format specifier, including
+integers and floats.  A good length for both integers and floats is 30, as
+this is more than generous, even if you're using doubles or long integers.
+
 * Use of functions
 ------------------