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<H1><A NAME="SECTION00240000000000000000"></A><A NAME="sec:Compatibility-with-previous"></A><A NAME="102"></A>
<BR>
1.4 Compatibility with previous
versions
</H1>
<P>
Newer versions have usually numerous bug fixes compared with the previous
version. But we also sometimes introduce some incompatibilities with
older versions. Not just for the fun of it, but to make the compiler
more stable, efficient and ANSI compliant<A NAME="103"></A>
(see section <A HREF="node183.html#sub:ANSI-Compliance">8.2</A> for ANSI-Compliance).
<BR>
<P>
<UL>
<LI>short is now equivalent to int (16 bits), it used to be equivalent
to char (8 bits) which is not ANSI compliant. To maintain compatibility,
old programs may be compiled using the --short-is-8bits commandline
option (see lyx:-short-is-8bits).
</LI>
<LI>the default directory for gcc-builds where include, library and documentation
files are stored is now in /usr/local/share.
</LI>
<LI>char type parameters to vararg<A NAME="107"></A>
functions are casted to int unless explicitly casted and <B>--std-c89<A NAME="108"></A></B>
and <B>--std-c99<A NAME="109"></A></B> command line
option are not defined, e.g.:
<BR><TT> char a=3;</TT>
<BR><TT> printf (%d %c\n,
a, (char)a);</TT>
<BR>
will push a as an int and as a char resp if <B>--std-c89<A NAME="114"></A></B>
and <B>--std-c99<A NAME="115"></A></B> command line
options are not defined,
<BR>
will push a as two ints if <B>--std-c89<A NAME="116"></A></B>
or <B>--std-c99<A NAME="117"></A></B> command line
option is defined.
</LI>
<LI>pointer type parameters to vararg<A NAME="118"></A>
functions are casted to generic pointers on harvard architectures
(e.g. mcs51, ds390) unless explicitly casted and <B>--std-c89<A NAME="119"></A></B>
and <B>--std-c99<A NAME="120"></A></B> command line
option are not defined.
</LI>
<LI>option --regextend has been removed.
</LI>
<LI>option --noregparms has been removed.
</LI>
<LI>option --stack-after-data has been removed.
</LI>
<LI>bit<A NAME="121"></A> and sbit<A NAME="122"></A><A NAME="123"></A> types
now consistently behave like the C99 _Bool type with respect to type
conversion<A NAME="124"></A><A NAME="125"></A>. The most
common incompatibility resulting from this change is related to bit
toggling<A NAME="126"></A> idioms, e.g.:
<BR><TT> bit b;</TT>
<BR><TT> b = ~<A NAME="5442"></A>b;
/* equivalent to b=1 instead of toggling b */</TT>
<BR><TT> b = !b; /* toggles b */</TT>
<BR>
In previous versions, both forms would have toggled the bit.
</LI>
<LI>in older versions, the preprocessor was always called with <B>--std-c99<A NAME="134"></A></B>
regardless of the <B>--std-xxx</B> setting. This is no longer
true, and can cause compilation failures on code built with <B>--std-c89<A NAME="136"></A></B>
but using c99 preprocessor features, such as one-line (//) comments
</LI>
<LI>in versions older than 2.8.4 the pic16 *printf() and printf_tiny()
library functions supported undocumented and not standard compliant
'b' binary format specifier (%b, %hb
and %lb). The 'b' specifier is now
disabled by default. It can be enabled by defining BINARY_SPECIFIER
macro in files device/lib/pic16/libc/stdio/vfprintf.c and device/lib/pic16/libc/stdio/printf_tiny.c
and recompiling the library.
</LI>
<LI>in versions older then 2.8.5 the unnamed bitfield structure members
participated in initialization, which is not conforming with ISO/IEC
9899:1999 standard (see section Section 6.7.8 Initialization, clause
9)
<BR>
<BR>
Old behavior, before version 2.8.5:
<BR><TT> struct {</TT>
<BR><TT> int a : 2;</TT>
<BR><TT> char : 2;</TT>
<BR><TT> int b : 2;</TT>
<BR><TT> } s = {1, 2, 3};</TT>
<BR><TT>/* s.a = 1, s.b = 3 */</TT>
<BR>
<BR>
New behavior:
<BR><TT> struct {</TT>
<BR><TT> int a : 2;</TT>
<BR><TT> char : 2;</TT>
<BR><TT> int b : 2;</TT>
<BR><TT> } s = {1, 2};</TT>
<BR><TT>/* s.a = 1, s.b = 2 */</TT>
</LI>
<LI>libraries, included in sdcc packages, are in ar format in sdcc version
2.9.0 and higher. See section <A HREF="node44.html#sub:Using-ar-to">3.1.6</A>.
</LI>
<LI>special sdcc keywords which are not preceded by a double underscore
are deprecated in version 3.0 and higher. See section <A HREF="node183.html#sub:ANSI-Compliance">8.2</A>
ANSI-Compliance.
</LI>
<LI>targets for xa51 and avr are disabled by default in version 3.0 and
higher.
</LI>
<LI>in sdcc version 3.0 and higher sdldgb and sdldz80 don't support generation
of GameBoy binary image format. The makebin utility can be used to
convert Intel Hex format to GameBoy binary image format.
</LI>
<LI>in sdcc version 3.0 and higher sdldgb and sdldz80 don't support generation
of rrgb (GameBoy simulator) map file and no$gmb symbol file formats.
The as2gbmap utility can be used to convert sdld map format to rrgb
and no$gmb file formats.
</LI>
</UL>
<P>
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