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+<chapter id="CodingSuggestions">
+<chapterinfo>
+ <author>
+ <firstname>Steve</firstname><surname>French</surname>
+ </author>
+ <author>
+ <firstname>Simo</firstname><surname>Sorce</surname>
+ </author>
+ <author>
+ <firstname>Andrew</firstname><surname>Bartlett</surname>
+ </author>
+ <author>
+ <firstname>Tim</firstname><surname>Potter</surname>
+ </author>
+ <author>
+ <firstname>Martin</firstname><surname>Pool</surname>
+ </author>
+</chapterinfo>
+
+<title>Coding Suggestions</title>
+
+<para>
+So you want to add code to Samba ...
+</para>
+
+<para>
+One of the daunting tasks facing a programmer attempting to write code for
+Samba is understanding the various coding conventions used by those most
+active in the project. These conventions were mostly unwritten and helped
+improve either the portability, stability or consistency of the code. This
+document will attempt to document a few of the more important coding
+practices used at this time on the Samba project. The coding practices are
+expected to change slightly over time, and even to grow as more is learned
+about obscure portability considerations. Two existing documents
+<filename>samba/source/internals.doc</filename> and
+<filename>samba/source/architecture.doc</filename> provide
+additional information.
+</para>
+
+<para>
+The loosely related question of coding style is very personal and this
+document does not attempt to address that subject, except to say that I
+have observed that eight character tabs seem to be preferred in Samba
+source. If you are interested in the topic of coding style, two oft-quoted
+documents are:
+</para>
+
+<para>
+<ulink url="http://lxr.linux.no/source/Documentation/CodingStyle">http://lxr.linux.no/source/Documentation/CodingStyle</ulink>
+</para>
+
+<para>
+<ulink url="http://www.fsf.org/prep/standards_toc.html">http://www.fsf.org/prep/standards_toc.html</ulink>
+</para>
+
+<para>
+But note that coding style in Samba varies due to the many different
+programmers who have contributed.
+</para>
+
+<para>
+Following are some considerations you should use when adding new code to
+Samba. First and foremost remember that:
+</para>
+
+<para>
+Portability is a primary consideration in adding function, as is network
+compatability with de facto, existing, real world CIFS/SMB implementations.
+There are lots of platforms that Samba builds on so use caution when adding
+a call to a library function that is not invoked in existing Samba code.
+Also note that there are many quite different SMB/CIFS clients that Samba
+tries to support, not all of which follow the SNIA CIFS Technical Reference
+(or the earlier Microsoft reference documents or the X/Open book on the SMB
+Standard) perfectly.
+</para>
+
+<para>
+Here are some other suggestions:
+</para>
+
+<orderedlist>
+
+<listitem><para>
+ use d_printf instead of printf for display text
+ reason: enable auto-substitution of translated language text
+</para></listitem>
+
+<listitem><para>
+ use SAFE_FREE instead of free
+ reason: reduce traps due to null pointers
+</para></listitem>
+
+<listitem><para>
+ don't use bzero use memset, or ZERO_STRUCT and ZERO_STRUCTP macros
+ reason: not POSIX
+</para></listitem>
+
+<listitem><para>
+ don't use strcpy and strlen (use safe_* equivalents)
+ reason: to avoid traps due to buffer overruns
+</para></listitem>
+
+<listitem><para>
+ don't use getopt_long, use popt functions instead
+ reason: portability
+</para></listitem>
+
+<listitem><para>
+ explicitly add const qualifiers on parm passing in functions where parm
+ is input only (somewhat controversial but const can be #defined away)
+</para></listitem>
+
+<listitem><para>
+ when passing a va_list as an arg, or assigning one to another
+ please use the VA_COPY() macro
+ reason: on some platforms, va_list is a struct that must be
+ initialized in each function...can SEGV if you don't.
+</para></listitem>
+
+<listitem><para>
+ discourage use of threads
+ reason: portability (also see architecture.doc)
+</para></listitem>
+
+<listitem><para>
+ don't explicitly include new header files in C files - new h files
+ should be included by adding them once to includes.h
+ reason: consistency
+</para></listitem>
+
+<listitem><para>
+ don't explicitly extern functions (they are autogenerated by
+ "make proto" into proto.h)
+ reason: consistency
+</para></listitem>
+
+<listitem><para>
+ use endian safe macros when unpacking SMBs (see byteorder.h and
+ internals.doc)
+ reason: not everyone uses Intel
+</para></listitem>
+
+<listitem><para>
+ Note Unicode implications of charset handling (see internals.doc). See
+ pull_* and push_* and convert_string functions.
+ reason: Internationalization
+</para></listitem>
+
+<listitem><para>
+ Don't assume English only
+ reason: See above
+</para></listitem>
+
+<listitem><para>
+ Try to avoid using in/out parameters (functions that return data which
+ overwrites input parameters)
+ reason: Can cause stability problems
+</para></listitem>
+
+<listitem><para>
+ Ensure copyright notices are correct, don't append Tridge's name to code
+ that he didn't write. If you did not write the code, make sure that it
+ can coexist with the rest of the Samba GPLed code.
+</para></listitem>
+
+<listitem><para>
+ Consider usage of DATA_BLOBs for length specified byte-data.
+ reason: stability
+</para></listitem>
+
+<listitem><para>
+ Take advantage of tdbs for database like function
+ reason: consistency
+</para></listitem>
+
+<listitem><para>
+ Don't access the SAM_ACCOUNT structure directly, they should be accessed
+ via pdb_get...() and pdb_set...() functions.
+ reason: stability, consistency
+</para></listitem>
+
+<listitem><para>
+ Don't check a password directly against the passdb, always use the
+ check_password() interface.
+ reason: long term pluggability
+</para></listitem>
+
+<listitem><para>
+ Try to use asprintf rather than pstrings and fstrings where possible
+</para></listitem>
+
+<listitem><para>
+ Use normal C comments / * instead of C++ comments // like
+ this. Although the C++ comment format is part of the C99
+ standard, some older vendor C compilers do not accept it.
+</para></listitem>
+
+<listitem><para>
+ Try to write documentation for API functions and structures
+ explaining the point of the code, the way it should be used, and
+ any special conditions or results. Mark these with a double-star
+ comment start / ** so that they can be picked up by Doxygen, as in
+ this file.
+</para></listitem>
+
+<listitem><para>
+ Keep the scope narrow. This means making functions/variables
+ static whenever possible. We don't want our namespace
+ polluted. Each module should have a minimal number of externally
+ visible functions or variables.
+</para></listitem>
+
+<listitem><para>
+ Use function pointers to keep knowledge about particular pieces of
+ code isolated in one place. We don't want a particular piece of
+ functionality to be spread out across lots of places - that makes
+ for fragile, hand to maintain code. Instead, design an interface
+ and use tables containing function pointers to implement specific
+ functionality. This is particularly important for command
+ interpreters.
+</para></listitem>
+
+<listitem><para>
+ Think carefully about what it will be like for someone else to add
+ to and maintain your code. If it would be hard for someone else to
+ maintain then do it another way.
+</para></listitem>
+
+</orderedlist>
+
+<para>
+The suggestions above are simply that, suggestions, but the information may
+help in reducing the routine rework done on new code. The preceeding list
+is expected to change routinely as new support routines and macros are
+added.
+</para>
+</chapter>