ANSI C - Revision history

Furey: Delinkify "pline". This section discusses several versions of pline with source code explicitly shown.

2024-06-28T10:59:49Z

Delinkify "pline". This section discusses several versions of pline with source code explicitly shown.

Furey: http -> https.

2024-06-20T20:06:05Z

http -> https.

Noisytoot: C17 is an ISO standard, not an ANSI standard

2023-11-21T19:39:55Z

C17 is an ISO standard, not an ANSI standard

Kufat: /* Note for the ambitious newbie */ C17 is now the latest released standard

2023-11-21T19:23:51Z

‎Note for the ambitious newbie: C17 is now the latest released standard

Netzhack: /* Prototypes */

2021-10-06T09:23:44Z

‎Prototypes

Aximili: changes to links

2020-03-20T04:31:33Z

changes to links

Netzhack: Added indication that pre-ANSI C is deprecated since 3.6.1.

2018-11-09T16:19:30Z

Added indication that pre-ANSI C is deprecated since 3.6.1.

Netzhack: /* Default promotions */ Full name of unsigned

2017-08-10T20:38:43Z

‎Default promotions: Full name of unsigned

Netzhack: Added missing word. I guess we've been reading phonetically all this time.

2017-08-10T20:32:38Z

Added missing word. I guess we've been reading phonetically all this time.

Ray Chason: USE_VARARGS uses va_arg; USE_STDARG does not

2014-11-16T23:48:08Z

USE_VARARGS uses va_arg; USE_STDARG does not

@@ Line 47: / Line 47: @@
 === Variable parameter lists ===
-The first C compilers used barely-portable hacks to support variadic functions such as {{function|pline.c|pline}}.  The symbol <code>USE_OLDARGS</code> enables these in NetHack.  Here is an abridgement of pline from [[NetHack 2.3e]]:
+The first C compilers used barely-portable hacks to support variadic functions such as <tt>pline</tt>.  The symbol <code>USE_OLDARGS</code> enables these in NetHack.  Here is an abridgement of pline from [[NetHack 2.3e]]:
   pline(line,arg1,arg2,arg3,arg4,arg5,arg6,arg7,arg8,arg9)

@@ Line 5: / Line 5: @@
 However, ''[[NetHack]]'' was a very old program dating from before ANSI C's first spec in 1989. Today's version can take advantage of certain ANSI C features, and code for this is in [[tradstdc.h]]. Is NetHack written in ANSI C? Yes and no, depending on what tradstdc.h decides to do.
-With the release of [[3.6.1]], the [[DevTeam]] has [http://nethack.org/devel/deprecation.html#361 announced] that most pre-ANSI syntax in the program is deprecated.
+With the release of [[3.6.1]], the [[DevTeam]] has [https://nethack.org/devel/deprecation.html#361 announced] that most pre-ANSI syntax in the program is deprecated.
 == The <code>void</code> type ==

@@ Line 99: / Line 99: @@
 many corrections and improvements and will cause you less trouble.
-If you choose to develop your code in C or C++, and are using something like gcc to compile, use the options <code>-Wall -ansi -pedantic</code>. You can also use <code>-std=c17</code> for the 2017 version of ANSI C.
+If you choose to develop your code in C or C++, and are using something like gcc to compile, use the options <code>-Wall -ansi -pedantic</code>. You can also use <code>-std=c17</code> for the 2017 version of ISO C.
 Vanilla NetHack continues to use C because of inertia (a 150,000+ line program is non-trivial to translate) and because of its stated goal:  to get the game working on as many different types of hardware and under as many different operating systems as is practical.
 [[Category:Development]]

@@ Line 96: / Line 96: @@
 == Note for the ambitious newbie ==
 In case you consider creating a project of your own, be it a Rogue-like game or some other application, consider using a more modern language than C. Nowadays there are lots of platform-independent, high-level alternatives like [[Wikipedia:Java (programming language)|Java]], [[Wikipedia:Python (programming language)|Python]] or [[Wikipedia:Perl|Perl]] just to mention a few. Such an application would
-be far easier to debug and maintain than its counterpart written in C. If you feel an urge to squeeze a bit more power out of the machine for your advanced ANSI-graphics and its pixelshading algorithms, at least consider using [[Wikipedia:C plus plus|C++]]. If you, despite every sane thought, decide that C is the language you want to use, use the latest version of C, [[Wikipedia:C (programming language)#C99|C99]]. The latest version contains
+be far easier to debug and maintain than its counterpart written in C. If you feel an urge to squeeze a bit more power out of the machine for your advanced ANSI-graphics and its pixelshading algorithms, at least consider using [[Wikipedia:C plus plus|C++]]. If you, despite every sane thought, decide that C is the language you want to use, use the latest version of C, [[Wikipedia:C (programming language)#C17|C17]]. The latest version contains
 many corrections and improvements and will cause you less trouble.
-If you choose to develop your code in C or C++, and are using something like gcc to compile, use the options <code>-Wall -ansi -pedantic</code>. You can also use <code>-std=c99</code> for the 1999 version of ANSI C.
+If you choose to develop your code in C or C++, and are using something like gcc to compile, use the options <code>-Wall -ansi -pedantic</code>. You can also use <code>-std=c17</code> for the 2017 version of ANSI C.
 Vanilla NetHack continues to use C because of inertia (a 150,000+ line program is non-trivial to translate) and because of its stated goal:  to get the game working on as many different types of hardware and under as many different operating systems as is practical.
 [[Category:Development]]

@@ Line 35: / Line 35: @@
   char *xname(struct obj *optr);
-The name of the parameter, <code>optr</code> in the example above, is optional; and NetHack usually omits it.
+The name of the parameter, <code>optr</code> in the example above, is optional; and NetHack usually omits it in forward declarations.
-The <code>NDECL</code>, <code>FDECL</code> and <code>VDECL</code> macros create either prototypes or old-style declarations.  <code>NDECL</code> is used if there are no parameters, <code>FDECL</code> for a fixed parameter list of at least one parameter, and <code>VDECL</code> for a variable parameter list. Separate macros are used to support an overlaid build on [[MS-DOS]] (which is not officially supported, and [https://groups.google.com/forum/?fromgroups=#!topic/rec.games.roguelike.nethack/4U8k5tRzV34 barely practical] today).
+The <code>NDECL</code>, <code>FDECL</code> and <code>VDECL</code> macros create either prototypes or old-style declarations.  <code>NDECL</code> is used if there are no parameters, <code>FDECL</code> for a fixed parameter list of at least one parameter, and <code>VDECL</code> for a variable parameter list. Separate macros are used to support building with overlays on [[MS-DOS]] (which is not officially supported, and [https://groups.google.com/forum/?fromgroups=#!topic/rec.games.roguelike.nethack/4U8k5tRzV34 barely practical] today).
 === Default promotions ===

@@ Line 1: / Line 1: @@
-In computer programming, '''ANSI C''' (or ''ISO C'', or ''C89'') is a specification for the [[C language]] and an update to the original K&R version of C. Programs written in the ANSI C language have access to a few extra features inspired by [[Wikipedia:C plus plus|C++]]; the main difference between old C and ANSI C seems to be in declarations of function parameters. These days, ANSI C is routine and C programmers almost always use it.
+{{wikipedia|C (programming language)}}
-* The Portland Pattern Repository [[wiki]] has a page: [[Wiki:AnsiCee]].
-* Wikipedia has one: [[Wikipedia:ANSI C]].
+In computer programming, '''ANSI C''' (or ''ISO C'', or ''C89'') is a specification for the C language and an update to the original K&R version of C. Programs written in the ANSI C language have access to a few extra features inspired by [[Wikipedia:C plus plus|C++]]; the main difference between old C and ANSI C seems to be in declarations of function parameters. These days, ANSI C is routine and C programmers almost always use it.
 However, ''[[NetHack]]'' was a very old program dating from before ANSI C's first spec in 1989. Today's version can take advantage of certain ANSI C features, and code for this is in [[tradstdc.h]]. Is NetHack written in ANSI C? Yes and no, depending on what tradstdc.h decides to do.
-With the release of Version 3.6.1, the DevTeam has [http://nethack.org/devel/deprecation.html#361 announced] that most pre-ANSI syntax in the program is deprecated.
+With the release of [[3.6.1]], the [[DevTeam]] has [http://nethack.org/devel/deprecation.html#361 announced] that most pre-ANSI syntax in the program is deprecated.
 == The <code>void</code> type ==

← Older revision		Revision as of 16:19, 9 November 2018
Line 4:		Line 4:

	However, ''[[NetHack]]'' was a very old program dating from before ANSI C's first spec in 1989. Today's version can take advantage of certain ANSI C features, and code for this is in [[tradstdc.h]]. Is NetHack written in ANSI C? Yes and no, depending on what tradstdc.h decides to do.		However, ''[[NetHack]]'' was a very old program dating from before ANSI C's first spec in 1989. Today's version can take advantage of certain ANSI C features, and code for this is in [[tradstdc.h]]. Is NetHack written in ANSI C? Yes and no, depending on what tradstdc.h decides to do.
		+
		+	With the release of Version 3.6.1, the DevTeam has [http://nethack.org/devel/deprecation.html#361 announced] that most pre-ANSI syntax in the program is deprecated.

	== The <code>void</code> type ==		== The <code>void</code> type ==

@@ Line 39: / Line 39: @@
 === Default promotions ===
-With the functions defined in the old style, integer types smaller than int are promoted to int or unsigned, preserving their signedness.  If a prototype is present, on most compilers the parameters must match the promoted types.  A few older compilers will match a prototype to an unpromoted parameter type.
+With the functions defined in the old style, integer types smaller than int are promoted to int or unsigned int, preserving their signedness.  If a prototype is present, on most compilers the parameters must match the promoted types.  A few older compilers will match a prototype to an unpromoted parameter type.
 [[global.h]] defines seven types to be used in prototypes where the function has a type with a default promotion.  The types are <code>CHAR_P</code>, <code>SCHAR_P</code>, <code>UCHAR_P</code>, <code>XCHAR_P</code>, <code>SHORT_P</code>, <code>BOOLEAN_P</code> and <code>ALIGNTYP_P</code>, and they correspond to <code>char</code>, <code>schar</code>, <code>uchar</code>, <code>xchar</code>, <code>short</code>, <code>boolean</code> and <code>aligntyp</code>.  The [[X11]] interface defines a <code>DIMENSION_P</code> type, corresponding to <code>Dimension</code>. (Not all of those types are ANSI C keywords: some are defined in library or other headers.)

@@ Line 59: / Line 59: @@
   #include <varargs.h>
   void
-  pline(format, va_alist)
+  pline(va_alist)
   va_dcl /* no semicolon */
+  {
       char pbuf[BUFSZ];
       va_list the_args;
       va_start(the_args);
       vsprintf(pbuf, format, the_args);
       va_end(the_args);
@@ Line 72: / Line 73: @@
+  }
-varargs.h also provides the macro <code>va_arg</code> to extract an argument from the list. NetHack calls it via the macro VA_INIT, defined in tradstd.h.
+The macro <code>va_arg</code> extracts an argument from the list. NetHack calls it via the macro VA_INIT, defined in tradstdc.h, if varargs.h is in use (but not if stdarg.h is in use).  The fixed arguments could also have been named explicitly in the function header.
 This usage could not be made compatible with prototypes, and so ANSI C uses a different system. <code>USE_STDARG</code> enables it in NetHack: