README.Coding: Add hint for if-statments

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Volker Lendecke <vl@samba.org>
Autobuild-Date(master): Mon Jan 19 13:25:12 CET 2015 on sn-devel-104

diff --git a/README.Coding b/README.Coding
index 0bbba9fc45e5fd756ff2b77df54e86a0cebeb607..f19399e7f24adf8c819f160e701fa0aa35c2dc4e 100644 (file)
--- a/README.Coding
+++ b/README.Coding
@@ -298,25 +298,6 @@ Good Examples:
        }
 
 
-Checking Pointer Values
------------------------
-
-When invoking functions that return pointer values, either of the following
-are acceptable. Use your best judgement and choose the more readable option.
-Remember that many other persons will review it:
-
-       if ((x = malloc(sizeof(short)*10)) == NULL ) {
-               fprintf(stderr, "Unable to alloc memory!\n");
-       }
-
-or:
-
-       x = malloc(sizeof(short)*10);
-       if (!x) {
-               fprintf(stderr, "Unable to alloc memory!\n");
-       }
-
-
 Primitive Data Types
 --------------------
 
@@ -364,6 +345,33 @@ Bad Example:
        ret = some_function_my_name(get_some_name());
        ...
 
+Please try to avoid passing function return values to if- or
+while-conditions. The reason for this is better handling of code under a
+debugger.
+
+Good example:
+
+       x = malloc(sizeof(short)*10);
+       if (!x) {
+               fprintf(stderr, "Unable to alloc memory!\n");
+       }
+
+Bad example:
+
+       if ((x = malloc(sizeof(short)*10)) == NULL ) {
+               fprintf(stderr, "Unable to alloc memory!\n");
+       }
+
+There are exceptions to this rule. One example is walking a data structure in
+an iterator style:
+
+       while ((opt = poptGetNextOpt(pc)) != -1) {
+                  ... do something with opt ...
+       }
+
+But in general, please try to avoid this pattern.
+
+
 Control-Flow changing macros
 ----------------------------