<LI><A HREF="#no_stl">Don't use STL</A></LI>
<LI><A HREF="#no_fordecl">Don't declare variables inside <TT>for()</TT></A></LI>
<LI><A HREF="#no_nestedclasses">Don't use nested classes</A></LI>
+ </OL>
+ <BR>
+ <LI>Other compiler limitations</LI>
+ <OL>
<LI><A HREF="#no_ternarywithobjects">Use ternary operator ?: carefully</A></LI>
+ <LI><A HREF="#no_autoaggregate">Don't use initializers with automatic arrays</A></LI>
+ <LI><A HREF="#no_dtorswithoutctor">Always have at least one constructor in a class with destructor</A></LI>
</OL>
<BR>
<LI>General recommendations</LI>
<OL>
+ <LI><A HREF="#no_cppcommentsinc">No C++ comments in C code></A></LI>
<LI><A HREF="#no_globals">No global variables with constructor</A></LI>
<LI><A HREF="#no_warnings">Turn on all warnings and eradicate them</A></LI>
<LI><A HREF="#no_assume_sizeof">Don't rely on <TT>sizeof(int) == 2</TT>...</A></LI>
<P>A nice side effect is that you don't need to recompile all the files
including the header if you change the PrivateLibClass declaration (it's
an example of a more general interface/implementation separation idea).
+</OL>
+
+ <BR>
+ <LI>Other compiler limitations</B></LI><P>
+This section lists the less obvious limitations of the current C++ compilers
+which are less restrictive than the ones mentioned in the previous section but
+are may be even more dangerous as a program which compiles perfectly well on
+some platform and seems to use only standard C++ featurs may still fail to
+compile on another platform and/or with another compiler.
+<OL>
<P><LI><A NAME="no_ternarywithobjects"></A><B>Use ternary operator ?: carefully</B></LI><P>
The ternary operator <TT>?:</TT> shouldn't be used with objects (i.e. if any
of its operands are objects) because some compilers (notable Borland C++) fail
else
s = s2;
</PRE>
+
+ <P><LI><A NAME="no_autoaggregate"></A><B>Don't use initializers with automatic arrays</B></LI><P>
+The initializers for automatic array variables are not supported by some older
+compilers. For example, the following line
+<PRE>
+ int daysInMonth[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+</PRE>
+will fail to compile with HP-UX C++ compiler.
+<P><U>Workaround</U>: either make the array static or initialize each item
+separately: in the (stupid) example above, the array should be definitely
+declared as <TT>static const</TT> (assuming that the leap years are dealt with
+elsewhere somehow...) which is ok. When an array is really not const, you
+should initialize each element separately.
+
+ <P><LI><A NAME="no_dtorswithoutctor"></A><B>Always have at least one constructor in a class with destructor</B></LI><P>
+It is a good rule to follow in general, but some compilers (HP-UX) enforce it.
+So even if you are sure that the default constructor for your class is ok but
+it has a destructor, remember to add an empty default constructor to it.
</OL>
<BR>
also contains some C/C++ specific remarks in the end which are less
important.
<OL>
+ <P><LI><A NAME="no_cppcommentsinc"><B>No C++ comments in C code></B></LI><P>
+Never use C++ comments in C code - not all C compilers/preprocessors
+understand them. Although we're mainly concerned with C++ here, there are
+several files in wxWindows sources tree which are compiled with C compiler.
+Among them are <TT>include/wx/setup.h</TT> and <TT>include/wx/expr.h</TT>.
+
+Another thing related to C vs C++ preprocessor differences is that some old C
+preprocessors require that all directives start in the first column (while
+it's generally allowed to have any amount of whitespace before them in C++),
+so you should start them in the beginning of the line in files which are
+compiled with C compiler.
+
<P><LI><A NAME="no_globals"></A><B>No global variables with constructors</B></LI><P>
In C++, the constructors of global variables are called before the
<TT>main()</TT> function (or <TT>WinMain()</TT> or any other program entry point)
The linker on VMS is case-insensitive. Therefore all external variables and
functions which differ only in case are not recognized by the linker as
different, so all externals should differ in more than the case only:
-i.e. <TT>GetId</TT> is the same as <TT><GetID</TT>.
+i.e. <TT>GetId</TT> is the same as <TT>GetID</TT>.
</OL>
The reason for the strange syntax for data is that some compilers use different
keyword ordering for exporting data.
-<P>There also several other places where you should take care of shared
-library case: all IMPLEMENT_xxx macros which are usually used in the
-corresponding .cpp files must be taken inside
-"<TT>#if !USE_SHARED_LIBRARY</TT>" and in the <TT>#if USE_SHARED_LIBRARY</TT>
-case you should put them inside <TT>common/cmndata.cpp</TT> file.
-
<P><LI><A NAME="set_get"></LI><B>Use Set/Get prefixes for accessors</B><P>
There is a convention in wxWindows to prefix the accessors (i.e. any simple, in
general, inline function which does nothing else except changing or returning
projects / wxWidgets.git / blobdiff