Author: particle
Date: Tue May 8 08:30:57 2007
New Revision: 18464
Modified:
trunk/docs/pdds/pdd07_codingstd.pod
Log:
#42903: [PATCH] Add guards to the rest of the headerfiles
~ include reason for new standard
~ increase precision in definition
~ correct indentation from prior commit
~ modify example to clarify use of nested preprocessor macros
Modified: trunk/docs/pdds/pdd07_codingstd.pod
==============================================================================
--- trunk/docs/pdds/pdd07_codingstd.pod (original)
+++ trunk/docs/pdds/pdd07_codingstd.pod Tue May 8 08:30:57 2007
@@ -256,22 +256,24 @@
=item *
-Header files must be wrapped with guard macros, which must have a PARROT_,
-followed by some unique and descriptive text identifying the header file, and
-be followed with a _GUARD suffix. The matching #endif must have the guard
+Header files must be wrapped with guard macros to prevent header redefinition.
+The guard macro must begin with C<PARROT_>, followed by unique and descriptive
+text identifying the header file (usually the directory path and filename,)
+and end with a C<_GUARD> suffix. The matching C<#endif> must have the guard
macro name in a comment, to prevent confusion. For example, a file named
-parrot/foo.h might look like:
+F<parrot/foo.h> might look like:
#ifndef PARROT_FOO_H_GUARD
- # define PARROT_FOO_H_GUARD
-
- # include "parrot/config.h"
- # ifdef PARROT_HAS_FEATURE_FOO
+ #define PARROT_FOO_H_GUARD
+
+ #include "parrot/config.h"
+ #ifdef PARROT_HAS_FEATURE_FOO
+ # define FOO_TYPE bar
typedef struct foo {
- ...
+ ...
} foo_t;
- # endif /* PARROT_HAS_FEATURE_FOO */
-
+ #endif /* PARROT_HAS_FEATURE_FOO */
+
#endif /* PARROT_FOO_H_GUARD */
=back
