netns: Don't receive new packets in a dead network namespace.

[linux-2.6-omap-h63xx.git] / Documentation / kernel-doc-nano-HOWTO.txt

diff --git a/Documentation/kernel-doc-nano-HOWTO.txt b/Documentation/kernel-doc-nano-HOWTO.txt
index c65233d430f0bb6888117c251576422d3fa9811f..0bd32748a467be8e7436f4ff3ec684b784755663 100644 (file)
--- a/Documentation/kernel-doc-nano-HOWTO.txt
+++ b/Documentation/kernel-doc-nano-HOWTO.txt
@@ -1,6 +1,105 @@
 kernel-doc nano-HOWTO
 =====================
 
 kernel-doc nano-HOWTO
 =====================
 

+How to format kernel-doc comments
+---------------------------------
+
+In order to provide embedded, 'C' friendly, easy to maintain,
+but consistent and extractable documentation of the functions and
+data structures in the Linux kernel, the Linux kernel has adopted
+a consistent style for documenting functions and their parameters,
+and structures and their members.
+
+The format for this documentation is called the kernel-doc format.
+It is documented in this Documentation/kernel-doc-nano-HOWTO.txt file.
+
+This style embeds the documentation within the source files, using
+a few simple conventions.  The scripts/kernel-doc perl script, some
+SGML templates in Documentation/DocBook, and other tools understand
+these conventions, and are used to extract this embedded documentation
+into various documents.
+
+In order to provide good documentation of kernel functions and data
+structures, please use the following conventions to format your
+kernel-doc comments in Linux kernel source.
+
+We definitely need kernel-doc formatted documentation for functions
+that are exported to loadable modules using EXPORT_SYMBOL.
+
+We also look to provide kernel-doc formatted documentation for
+functions externally visible to other kernel files (not marked
+"static").
+
+We also recommend providing kernel-doc formatted documentation
+for private (file "static") routines, for consistency of kernel
+source code layout.  But this is lower priority and at the
+discretion of the MAINTAINER of that kernel source file.
+
+Data structures visible in kernel include files should also be
+documented using kernel-doc formatted comments.
+
+The opening comment mark "/**" is reserved for kernel-doc comments.
+Only comments so marked will be considered by the kernel-doc scripts,
+and any comment so marked must be in kernel-doc format.  Do not use
+"/**" to be begin a comment block unless the comment block contains
+kernel-doc formatted comments.  The closing comment marker for
+kernel-doc comments can be either "*/" or "**/".
+
+Kernel-doc comments should be placed just before the function
+or data structure being described.
+
+Example kernel-doc function comment:
+
+/**
+ * foobar() - short function description of foobar
+ * @arg1:      Describe the first argument to foobar.
+ * @arg2:      Describe the second argument to foobar.
+ *             One can provide multiple line descriptions
+ *             for arguments.
+ *
+ * A longer description, with more discussion of the function foobar()
+ * that might be useful to those using or modifying it.  Begins with
+ * empty comment line, and may include additional embedded empty
+ * comment lines.
+ *
+ * The longer description can have multiple paragraphs.
+ **/
+
+The first line, with the short description, must be on a single line.
+
+The @argument descriptions must begin on the very next line following
+this opening short function description line, with no intervening
+empty comment lines.
+
+Example kernel-doc data structure comment.
+
+/**
+ * struct blah - the basic blah structure
+ * @mem1:      describe the first member of struct blah
+ * @mem2:      describe the second member of struct blah,
+ *             perhaps with more lines and words.
+ *
+ * Longer description of this structure.
+ **/
+
+The kernel-doc function comments describe each parameter to the
+function, in order, with the @name lines.
+
+The kernel-doc data structure comments describe each structure member
+in the data structure, with the @name lines.
+
+The longer description formatting is "reflowed", losing your line
+breaks.  So presenting carefully formatted lists within these
+descriptions won't work so well; derived documentation will lose
+the formatting.
+
+See the section below "How to add extractable documentation to your
+source files" for more details and notes on how to format kernel-doc
+comments.
+
+Components of the kernel-doc system
+-----------------------------------
+

 Many places in the source tree have extractable documentation in the
 form of block comments above functions.  The components of this system
 are:
 Many places in the source tree have extractable documentation in the
 form of block comments above functions.  The components of this system
 are:


@@ -17,7 +116,7 @@ are:
   special place-holders for where the extracted documentation should
   go.
 
   special place-holders for where the extracted documentation should
   go.
 

-- scripts/docproc.c
+- scripts/basic/docproc.c

 
   This is a program for converting SGML template files into SGML
   files. When a file is referenced it is searched for symbols
 
   This is a program for converting SGML template files into SGML
   files. When a file is referenced it is searched for symbols


@@ -101,16 +200,20 @@ The format of the block comment is like this:
 
 /**
  * function_name(:)? (- short description)?
 
 /**
  * function_name(:)? (- short description)?

-(* @parameterx: (description of parameter x)?)*
+(* @parameterx(space)*: (description of parameter x)?)*

 (* a blank line)?
  * (Description:)? (Description of function)?
  * (section header: (section description)? )*
 (*)?*/
 
 (* a blank line)?
  * (Description:)? (Description of function)?
  * (section header: (section description)? )*
 (*)?*/
 

-The short function description cannot be multiline, but the other
-descriptions can be (and they can contain blank lines). Avoid putting a
-spurious blank line after the function name, or else the description will
-be repeated!
+The short function description ***cannot be multiline***, but the other
+descriptions can be (and they can contain blank lines).  If you continue
+that initial short description onto a second line, that second line will
+appear further down at the beginning of the description section, which is
+almost certainly not what you had in mind.
+
+Avoid putting a spurious blank line after the function name, or else the
+description will be repeated!

 
 All descriptive text is further processed, scanning for the following special
 patterns, which are highlighted appropriately.
 
 All descriptive text is further processed, scanning for the following special
 patterns, which are highlighted appropriately.


@@ -121,6 +224,31 @@ patterns, which are highlighted appropriately.
 '@parameter' - name of a parameter
 '%CONST' - name of a constant.
 
 '@parameter' - name of a parameter
 '%CONST' - name of a constant.
 

+NOTE 1:  The multi-line descriptive text you provide does *not* recognize
+line breaks, so if you try to format some text nicely, as in:
+
+  Return codes
+    0 - cool
+    1 - invalid arg
+    2 - out of memory
+
+this will all run together and produce:
+
+  Return codes 0 - cool 1 - invalid arg 2 - out of memory
+
+NOTE 2:  If the descriptive text you provide has lines that begin with
+some phrase followed by a colon, each of those phrases will be taken as
+a new section heading, which means you should similarly try to avoid text
+like:
+
+  Return codes:
+    0: cool
+    1: invalid arg
+    2: out of memory
+
+every line of which would start a new section.  Again, probably not
+what you were after.
+

 Take a look around the source tree for examples.
 
 
 Take a look around the source tree for examples.