- Macro ANSI C definition Traditional C definition
- ----- ---- - ---------- ----------- - ----------
- PTR `void *' `char *'
- LONG_DOUBLE `long double' `double'
- VOLATILE `volatile' `'
- SIGNED `signed' `'
- PTRCONST `void *const' `char *'
- ANSI_PROTOTYPES 1 not defined
-
- CONST is also defined, but is obsolete. Just use const.
-
- obsolete -- DEFUN (name, arglist, args)
-
- Defines function NAME.
-
- ARGLIST lists the arguments, separated by commas and enclosed in
- parentheses. ARGLIST becomes the argument list in traditional C.
-
- ARGS list the arguments with their types. It becomes a prototype in
- ANSI C, and the type declarations in traditional C. Arguments should
- be separated with `AND'. For functions with a variable number of
- arguments, the last thing listed should be `DOTS'.
-
- obsolete -- DEFUN_VOID (name)
-
- Defines a function NAME, which takes no arguments.
-
- obsolete -- EXFUN (name, (prototype)) -- obsolete.
-
- Replaced by PARAMS. Do not use; will disappear someday soon.
- Was used in external function declarations.
- In ANSI C it is `NAME PROTOTYPE' (so PROTOTYPE should be enclosed in
- parentheses). In traditional C it is `NAME()'.
- For a function that takes no arguments, PROTOTYPE should be `(void)'.
-
- obsolete -- PROTO (type, name, (prototype) -- obsolete.
-
- This one has also been replaced by PARAMS. Do not use.
-
- PARAMS ((args))
-
- We could use the EXFUN macro to handle prototype declarations, but
- the name is misleading and the result is ugly. So we just define a
- simple macro to handle the parameter lists, as in:
-
- static int foo PARAMS ((int, char));
-
- This produces: `static int foo();' or `static int foo (int, char);'
-
- EXFUN would have done it like this:
-
- static int EXFUN (foo, (int, char));
-
- but the function is not external...and it's hard to visually parse
- the function name out of the mess. EXFUN should be considered
- obsolete; new code should be written to use PARAMS.
-
- DOTS is also obsolete.
-
- Examples:
-
- extern int printf PARAMS ((const char *format, ...));
-*/
+ Macro ANSI C definition Traditional C definition
+ ----- ---- - ---------- ----------- - ----------
+ ANSI_PROTOTYPES 1 not defined
+ PTR `void *' `char *'
+ PTRCONST `void *const' `char *'
+ LONG_DOUBLE `long double' `double'
+ const not defined `'
+ volatile not defined `'
+ signed not defined `'
+ VA_START(ap, var) va_start(ap, var) va_start(ap)
+
+ Note that it is safe to write "void foo();" indicating a function
+ with no return value, in all K+R compilers we have been able to test.
+
+ For declaring functions with prototypes, we also provide these:
+
+ PARAMS ((prototype))
+ -- for functions which take a fixed number of arguments. Use this
+ when declaring the function. When defining the function, write a
+ K+R style argument list. For example:
+
+ char *strcpy PARAMS ((char *dest, char *source));
+ ...
+ char *
+ strcpy (dest, source)
+ char *dest;
+ char *source;
+ { ... }
+
+
+ VPARAMS ((prototype, ...))
+ -- for functions which take a variable number of arguments. Use
+ PARAMS to declare the function, VPARAMS to define it. For example:
+
+ int printf PARAMS ((const char *format, ...));
+ ...
+ int
+ printf VPARAMS ((const char *format, ...))
+ {
+ ...
+ }
+
+ For writing functions which take variable numbers of arguments, we
+ also provide the VA_OPEN, VA_CLOSE, and VA_FIXEDARG macros. These
+ hide the differences between K+R <varargs.h> and C89 <stdarg.h> more
+ thoroughly than the simple VA_START() macro mentioned above.
+
+ VA_OPEN and VA_CLOSE are used *instead of* va_start and va_end.
+ Immediately after VA_OPEN, put a sequence of VA_FIXEDARG calls
+ corresponding to the list of fixed arguments. Then use va_arg
+ normally to get the variable arguments, or pass your va_list object
+ around. You do not declare the va_list yourself; VA_OPEN does it
+ for you.
+
+ Here is a complete example:
+
+ int
+ printf VPARAMS ((const char *format, ...))
+ {
+ int result;
+
+ VA_OPEN (ap, format);
+ VA_FIXEDARG (ap, const char *, format);
+
+ result = vfprintf (stdout, format, ap);
+ VA_CLOSE (ap);
+
+ return result;
+ }
+
+
+ You can declare variables either before or after the VA_OPEN,
+ VA_FIXEDARG sequence. Also, VA_OPEN and VA_CLOSE are the beginning
+ and end of a block. They must appear at the same nesting level,
+ and any variables declared after VA_OPEN go out of scope at
+ VA_CLOSE. Unfortunately, with a K+R compiler, that includes the
+ argument list. You can have multiple instances of VA_OPEN/VA_CLOSE
+ pairs in a single function in case you need to traverse the
+ argument list more than once.
+
+ For ease of writing code which uses GCC extensions but needs to be
+ portable to other compilers, we provide the GCC_VERSION macro that
+ simplifies testing __GNUC__ and __GNUC_MINOR__ together, and various
+ wrappers around __attribute__. Also, __extension__ will be #defined
+ to nothing if it doesn't work. See below.
+
+ This header also defines a lot of obsolete macros:
+ CONST, VOLATILE, SIGNED, PROTO, EXFUN, DEFUN, DEFUN_VOID,
+ AND, DOTS, NOARGS. Don't use them. */