-signed keyword
---------------
-
-The signed keyword did not exist in K+R comilers, it was introduced in
-ISO C89, so you cannot use it. In both K+R and standard C,
-unqualified char and bitfields may be signed or unsigned. There is no
-way to portably declare signed chars or signed bitfields.
-
-All other arithmetic types are signed unless you use the 'unsigned'
-qualifier. For instance, it is safe to write
-
- short paramc;
-
-instead of
-
- signed short paramc;
-
-If you have an algorithm that depends on signed char or signed
-bitfields, you must find another way to write it before it can be
-integrated into GCC.
-
-
-Function prototypes
--------------------
-
-You need to provide a function prototype for every function before you
-use it, and functions must be defined K+R style. The function
-prototype should use the PARAMS macro, which takes a single argument.
-Therefore the parameter list must be enclosed in parentheses. For
-example,
-
-int myfunc PARAMS ((double, int *));
-
-int
-myfunc (var1, var2)
- double var1;
- int *var2;
-{
- ...
-}
-
-You also need to use PARAMS when referring to function protypes in
-other circumstances, for example see "Calling functions through
-pointers to functions" below.
-
-Variable-argument functions are best described by example:-
-
-void cpp_ice PARAMS ((cpp_reader *, const char *msgid, ...));
-
-void
-cpp_ice VPARAMS ((cpp_reader *pfile, const char *msgid, ...))
-{
-#ifndef ANSI_PROTOTYPES
- cpp_reader *pfile;
- const char *msgid;
-#endif
- va_list ap;
-
- VA_START (ap, msgid);
-
-#ifndef ANSI_PROTOTYPES
- pfile = va_arg (ap, cpp_reader *);
- msgid = va_arg (ap, const char *);
-#endif
-
- ...
- va_end (ap);
-}
-
-For the curious, here are the definitions of the above macros. See
-ansidecl.h for the definitions of the above macros and more.
-
-#define PARAMS(paramlist) paramlist /* ISO C. */
-#define VPARAMS(args) args
-
-#define PARAMS(paramlist) () /* K+R C. */
-#define VPARAMS(args) (va_alist) va_dcl
-
-
-Calling functions through pointers to functions
------------------------------------------------
-
-K+R C compilers require brackets around the dereferenced pointer
-variable. For example
-
-typedef void (* cl_directive_handler) PARAMS ((cpp_reader *, const char *));
- p->handler (pfile, p->arg);
-
-needs to become
-
- (p->handler) (pfile, p->arg);
-
-
-Macros
-------
-
-The rules under K+R C and ISO C for achieving stringification and
-token pasting are quite different. Therefore some macros have been
-defined which will get it right depending upon the compiler.
-
- CONCAT2(a,b) CONCAT3(a,b,c) and CONCAT4(a,b,c,d)
-
-will paste the tokens passed as arguments. You must not leave any
-space around the commas. Also,
-
- STRINGX(x)
-
-will stringify an argument; to get the same result on K+R and ISO
-compilers x should not have spaces around it.
-
-
-Enums
------
-
-In K+R C, you have to cast enum types to use them as integers, and
-some compilers in particular give lots of warnings for using an enum
-as an array index.
-
-Bitfields
----------
-
-See also "signed keyword" above. In K+R C only unsigned int bitfields
-were defined (i.e. unsigned char, unsigned short, unsigned long.
-Using plain int/short/long was not allowed).
-
-
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