[lmi-commits] [lmi] master a9228d2: Add a "Preprocessor Conditions" style item

[Vadim Zeitlin]

branch: master
commit a9228d23a6ed7b36177c7ccc49729afd881d870f
Author: Vadim Zeitlin <address@hidden>
Commit: Vadim Zeitlin <address@hidden>

    Add a "Preprocessor Conditions" style item
    
    Document that `#if defined` should be preferred to `#ifdef`.
---
 vz/Style-guide.md | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/vz/Style-guide.md b/vz/Style-guide.md
index 01b81eb..a61ff4f 100644
--- a/vz/Style-guide.md
+++ b/vz/Style-guide.md
@@ -156,6 +156,17 @@ Rationale: This makes it impossible to use an 
uninitialized field and avoids
 duplication of the same values among different constructors.
 
 
+Preprocessor Conditions
+-----------------------
+
+### Prefer `#if defined FOO` to `#ifdef FOO`
+
+Similarly, use `#if !defined FOO` rather than `#ifndef Foo`.
+
+Also write the comment after `#else` (if any) or `#endif` as `// defined FOO`
+for symmetry (rather than just `// FOO` which would match `#if FOO`).
+
+
 Special Member Functions
 ------------------------