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-rw-r--r--Documentation/CodingGuidelines22
1 files changed, 14 insertions, 8 deletions
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index f45db5b727..227f46ae40 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -75,7 +75,7 @@ For shell scripts specifically (not exhaustive):
- If you want to find out if a command is available on the user's
$PATH, you should use 'type <command>', instead of 'which <command>'.
- The output of 'which' is not machine parseable and its exit code
+ The output of 'which' is not machine parsable and its exit code
is not reliable across platforms.
- We use POSIX compliant parameter substitutions and avoid bashisms;
@@ -91,16 +91,10 @@ For shell scripts specifically (not exhaustive):
- No shell arrays.
- - No strlen ${#parameter}.
-
- No pattern replacement ${parameter/pattern/string}.
- We use Arithmetic Expansion $(( ... )).
- - Inside Arithmetic Expansion, spell shell variables with $ in front
- of them, as some shells do not grok $((x)) while accepting $(($x))
- just fine (e.g. dash older than 0.5.4).
-
- We do not use Process Substitution <(list) or >(list).
- Do not write control structures on a single line with semicolon.
@@ -203,7 +197,7 @@ For C programs:
. since early 2012 with e1327023ea, we have been using an enum
definition whose last element is followed by a comma. This, like
an array initializer that ends with a trailing comma, can be used
- to reduce the patch noise when adding a new identifer at the end.
+ to reduce the patch noise when adding a new identifier at the end.
. since mid 2017 with cbc0f81d, we have been using designated
initializers for struct (e.g. "struct t v = { .val = 'a' };").
@@ -238,6 +232,18 @@ For C programs:
while( condition )
func (bar+1);
+ - Do not explicitly compare an integral value with constant 0 or '\0',
+ or a pointer value with constant NULL. For instance, to validate that
+ counted array <ptr, cnt> is initialized but has no elements, write:
+
+ if (!ptr || cnt)
+ BUG("empty array expected");
+
+ and not:
+
+ if (ptr == NULL || cnt != 0);
+ BUG("empty array expected");
+
- We avoid using braces unnecessarily. I.e.
if (bla) {