ANSI C standard of zsh

ANSI C standard of zsh

[Clinton Bunch]

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I was looking at the development guide and saw this:

The primary language is ANSI C as defined by the 1989 standard, but the
   code should always be compatible with late K&R era compilers ("The C
   Programming Language" 1st edition, plus "void" and "enum").  There are
   many hacks to avoid the need to actually restrict the code to K&R C --
   check out the configure tests -- but always bear the compatibility
   requirements in mind.  In particular, preprocessing directives must
   have the "#" unindented, and string pasting is not available.

5.9 does not compile with gcc's c89 on EL 8 or 9 (Rocky specifically).
I intend to test FreeBSD and Solaris as well, but haven't yet.


I will point out the C99 standard is now a quarter century old. I 
propose that we update the development guide to remove the bit about the 
1989 standard (much less K&R compatibility) since it is no longer true, 
and I personally question if it even makes sense as a goal 30+ years in 
to development.

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Re: ANSI C standard of zsh

[Clinton Bunch]

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c89 will not build 5.9 on Solaris

On FreeBSD

configure with CC=c89 fails
  CC='cc -std=c89' is overridden by configure with -std=gnu11

On 3/12/2024 16:44, Clinton Bunch wrote:
>
> I was looking at the development guide and saw this:
>
> The primary language is ANSI C as defined by the 1989 standard, but the
>    code should always be compatible with late K&R era compilers ("The C
>    Programming Language" 1st edition, plus "void" and "enum").  There are
>    many hacks to avoid the need to actually restrict the code to K&R C --
>    check out the configure tests -- but always bear the compatibility
>    requirements in mind.  In particular, preprocessing directives must
>    have the "#" unindented, and string pasting is not available.
>
> 5.9 does not compile with gcc's c89 on EL 8 or 9 (Rocky specifically).
> I intend to test FreeBSD and Solaris as well, but haven't yet.
>
> I will point out the C99 standard is now a quarter century old. I 
> propose that we update the development guide to remove the bit about 
> the 1989 standard (much less K&R compatibility) since it is no longer 
> true, and I personally question if it even makes sense as a goal 30+ 
> years in to development.


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Re: ANSI C standard of zsh

[Bart Schaefer]

On Tue, Mar 12, 2024 at 2:44 PM Clinton Bunch <cdb_zsh@zentaur.org> wrote:
>
> I was looking at the development guide and saw this:
>
> The primary language is ANSI C as defined by the 1989 standard, but the
>   code should always be compatible with late K&R era compilers ("The C
>   Programming Language" 1st edition, plus "void" and "enum").  There are
>   many hacks to avoid the need to actually restrict the code to K&R C --
>   check out the configure tests -- but always bear the compatibility
>   requirements in mind.  In particular, preprocessing directives must
>   have the "#" unindented, and string pasting is not available.
>
> 5.9 does not compile with gcc's c89 on EL 8 or 9 (Rocky specifically).
> I intend to test FreeBSD and Solaris as well, but haven't yet.
>
>
> I will point out the C99 standard is now a quarter century old. I propose that we update the development guide to remove the bit about the 1989 standard (much less K&R compatibility) since it is no longer true, and I personally question if it even makes sense as a goal 30+ years in to development.

Re: ANSI C standard of zsh

[Bart Schaefer]

(Believe it or not, my cat stepped on the laptop while I was
drag-selecting and that hit the send button)

On Tue, Mar 12, 2024 at 2:44 PM Clinton Bunch <cdb_zsh@zentaur.org> wrote:
>
>  I propose that we update the development guide to remove the bit about the 1989 standard (much less K&R compatibility) since it is no longer true, and I personally question if it even makes sense as a goal 30+ years in to development.

I think we pretty much agreed on that back in December (workers/51212
anyone?) and just never edited that bit of the document.

Re: ANSI C standard of zsh

[Oliver Kiddle]

Bart Schaefer wrote:
> On Tue, Mar 12, 2024 at 2:44 PM Clinton Bunch <cdb_zsh@zentaur.org> wrote:
> >  I propose that we update the development guide to remove the bit about the 1989 standard (much less K&R compatibility) since it is no longer true, and I personally question if it even makes sense as a goal 30+ years in to development.

No objections from me. Replacement wording would be welcome. We're using
string pasting (##) in quite a few places despite that being "not
available".

stdbool.h apparently already gets used in wcwidth9.h but
--enable-unicode9 is also something whose time has passed and which
should be removed.

It may also be useful to consider things like whether stdbool.h should
be included once from zsh_system.h

> I think we pretty much agreed on that back in December (workers/51212
> anyone?) and just never edited that bit of the document.

The sentiment there was similar but the legacy code removed at that
point likely ceased to be relevant even before C99 was defined.

I wouldn't draw too many conclusions from zsh failing to compile with
c89. The errors mostly come from system header files. Often the
standards options enforce a level of strictness that can be absent with
default options. With the right vintage C compiler, you'll likely find
that specifying the C99 standard also breaks the build, sometimes even
with -std=gnu99.

It was quite some time after 1999 before C99 became usable. C++ was
higher priority for the compiler writers at that time. I think the
K&R support continued to be relevant for long after the ANSI standard
because some Unix vendors (HP?) included a basic K&R compiler with the
OS but charged extra for the newer one. But I doubt anyone has needed
ansi2knr in a long time. The attached patch strips out all the ansi2knr
support.

There's something for ._foo_ file extensions in Makemod.in.in that looks
like someone's leftover debug from years back. Or does it have a strange
purpose I couldn't fathom? It's possible that I've missed a use of the
_(Args) macro buried somewhere in conditional code. We had logic in
aclocal.m4 to select appropriate compiler options to select ansi form.
Perhaps some of this is still actually relevant but it seemed better to
clear it. From memory I was always forcing -xansi into CFLAGS on IRIX
manually and the same approach would still be open. I also needed to
mark a couple of #ifdefs for makepro.awk to keep them in utils.c where a
function conditionally had a macro replacement. With different results
from configure, similar problems may remain elsewhere.

Oliver

diff --git a/Config/defs.mk.in b/Config/defs.mk.in
index 2bc17482a..116875fb9 100644
--- a/Config/defs.mk.in
+++ b/Config/defs.mk.in
@@ -75,7 +75,6 @@ IMPOPT          = @IMPOPT@
 
 # utilities
 AWK             = @AWK@
-ANSI2KNR        = @ANSI2KNR@
 YODL            = @YODL@ @YODL_OPTIONS@
 YODL2TXT        = @YODL@2txt
 YODL2HTML       = @YODL@2html
@@ -100,7 +99,7 @@ LDFLAGS='$(LDFLAGS)' EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)' \
 DLCFLAGS='$(DLCFLAGS)' DLLDFLAGS='$(DLLDFLAGS)' \
 LIBLDFLAGS='$(LIBLDFLAGS)' EXELDFLAGS='$(EXELDFLAGS)' \
 LIBS='$(LIBS)' DL_EXT='$(DL_EXT)' DLLD='$(DLLD)' \
-AWK='$(AWK)' ANSI2KNR='$(ANSI2KNR)' \
+AWK='$(AWK)' \
 YODL='$(YODL)' YODL2TXT='$(YODL2TXT)' YODL2HTML='$(YODL2HTML)' \
 FUNCTIONS_INSTALL='$(FUNCTIONS_INSTALL)' tzsh='$(tzsh)'
 
diff --git a/Etc/zsh-development-guide b/Etc/zsh-development-guide
index 5cb542709..bdabe17d8 100644
--- a/Etc/zsh-development-guide
+++ b/Etc/zsh-development-guide
@@ -240,7 +240,7 @@ C coding style
   There must be an empty line, a line with "/**/", a line with the
   type of the function, and finally the name of the function with typed
   arguments.  These lines must not be indented.  The script generating
-  function prototypes and the ansi2knr program depend on this format.
+  function prototypes depends on this format.
 
 * Variable declarations must similarly be preceded by a
   line containing only "/**/", for the prototype generation script.
diff --git a/Src/Makemod.in.in b/Src/Makemod.in.in
index ea0cdc3a4..3343ae1d0 100644
--- a/Src/Makemod.in.in
+++ b/Src/Makemod.in.in
@@ -52,32 +52,17 @@ DLCOMPILE   = $(CC) -c -I. -I$(dir_top)/Src -I$(sdir_top)/Src -I$(sdir_top)/Src/
 LINK        = $(CC) $(LDFLAGS) $(EXELDFLAGS) $(EXTRA_LDFLAGS) -o $@
 DLLINK      = $(DLLD) $(LDFLAGS) $(LIBLDFLAGS) $(DLLDFLAGS) -o $@
 
-KNR_OBJ=.o
-KNROBJ=._foo_
+OBJ=.o
 
-ANSIOBJ=.o
-ANSI_OBJ=._foo_
+.SUFFIXES: .c .$(DL_EXT) ..o .o .syms .pro .epro
 
-.SUFFIXES: .c .$(DL_EXT) ..o .._foo_ .o ._foo_ .syms .pro .epro
-
-.c$(ANSI@U@OBJ):
+.c$(OBJ):
 	$(COMPILE) -o $@ $<
 	@rm -f $(dir_src)/stamp-modobjs
 
-.c$(KNR@U@OBJ):
-	@ANSI2KNR@ $< > $@.c
-	$(COMPILE) -o $@ $@.c
-	rm -f $@.c
-	@rm -f $(dir_src)/stamp-modobjs
-
-.c.$(ANSI@U@OBJ):
+.c.$(OBJ):
 	$(DLCOMPILE) -o $@ $<
 
-.c.$(KNR@U@OBJ):
-	@ANSI2KNR@ $< > $@.c
-	$(DLCOMPILE) -o $@ $@.c
-	rm -f $@.c
-
 .c.syms:
 	$(AWK) -f $(sdir_src)/makepro.awk $< $(subdir) > $@
 
diff --git a/Src/Modules/files.c b/Src/Modules/files.c
index bf0e8f8a8..a3fec1daa 100644
--- a/Src/Modules/files.c
+++ b/Src/Modules/files.c
@@ -29,8 +29,8 @@
 
 #include "files.mdh"
 
-typedef int (*MoveFunc) _((char const *, char const *));
-typedef int (*RecurseFunc) _((char *, char *, struct stat const *, void *));
+typedef int (*MoveFunc) (char const *, char const *);
+typedef int (*RecurseFunc) (char *, char *, struct stat const *, void *);
 
 struct recursivecmd;
 
diff --git a/Src/Modules/watch.c b/Src/Modules/watch.c
index ba17cf940..acc499518 100644
--- a/Src/Modules/watch.c
+++ b/Src/Modules/watch.c
@@ -584,7 +584,7 @@ readwtab(WATCH_STRUCT_UTMP **head, int initial_sz)
 
     if (sz)
 	qsort((void *) *head, sz, sizeof(WATCH_STRUCT_UTMP),
-	           (int (*) _((const void *, const void *)))ucmp);
+	           (int (*) (const void *, const void *))ucmp);
     return sz;
 }
 
diff --git a/Src/Modules/zftp.c b/Src/Modules/zftp.c
index 47a5e9de9..0c26828fd 100644
--- a/Src/Modules/zftp.c
+++ b/Src/Modules/zftp.c
@@ -127,7 +127,7 @@ typedef int (*readwrite_t)(int, char *, off_t, int);
 
 struct zftpcmd {
     const char *nam;
-    int (*fun) _((char *, char **, int));
+    int (*fun) (char *, char **, int);
     int min, max, flags;
 };
 
diff --git a/Src/Modules/zprof.c b/Src/Modules/zprof.c
index 56cdab888..171a15b90 100644
--- a/Src/Modules/zprof.c
+++ b/Src/Modules/zprof.c
@@ -163,9 +163,9 @@ bin_zprof(UNUSED(char *nam), UNUSED(char **args), Options ops, UNUSED(int func))
 	*ap = NULL;
 
 	qsort(fs, ncalls, sizeof(f),
-	      (int (*) _((const void *, const void *))) cmpsfuncs);
+	      (int (*) (const void *, const void *)) cmpsfuncs);
 	qsort(as, narcs, sizeof(a),
-	      (int (*) _((const void *, const void *))) cmpparcs);
+	      (int (*) (const void *, const void *)) cmpparcs);
 
 	printf("num  calls                time                       self            name\n-----------------------------------------------------------------------------------\n");
 	for (fp = fs, i = 1; *fp; fp++, i++) {
@@ -179,7 +179,7 @@ bin_zprof(UNUSED(char *nam), UNUSED(char **args), Options ops, UNUSED(int func))
 		   (*fp)->name);
 	}
 	qsort(fs, ncalls, sizeof(f),
-	      (int (*) _((const void *, const void *))) cmptfuncs);
+	      (int (*) (const void *, const void *)) cmptfuncs);
 
 	for (fp = fs; *fp; fp++) {
 	    printf("\n-----------------------------------------------------------------------------------\n\n");
diff --git a/Src/Zle/compcore.c b/Src/Zle/compcore.c
index 9b87cad93..09282d42d 100644
--- a/Src/Zle/compcore.c
+++ b/Src/Zle/compcore.c
@@ -3253,7 +3253,7 @@ makearray(LinkList l, int type, int flags, int *np, int *nlp, int *llp)
 	    /* Now sort the array (it contains matches). */
 	    matchorder = flags;
 	    qsort((void *) rp, n, sizeof(Cmatch),
-		  (int (*) _((const void *, const void *)))matchcmp);
+		  (int (*) (const void *, const void *))matchcmp);
 
 	    /* since the matches are sorted and the default is to remove
 	     * all duplicates, -1 (remove only consecutive dupes) is a no-op,
@@ -3295,7 +3295,7 @@ makearray(LinkList l, int type, int flags, int *np, int *nlp, int *llp)
 		sp = (Cmatch *) zhalloc((n + 1) * sizeof(Cmatch));
 		memcpy(sp, rp, (n + 1) * sizeof(Cmatch));
 		qsort((void *) sp, n, sizeof(Cmatch),
-		      (int (*) _((const void *, const void *)))matchcmp);
+		      (int (*) (const void *, const void *))matchcmp);
 		for (asp = sp + 1; *asp; asp++) {
 		    Cmatch *ap = asp - 1, *bp = asp;
 		    if (matcheq(*ap, *bp)) {
diff --git a/Src/Zle/zle.h b/Src/Zle/zle.h
index 010ead3d2..5bb9e7a5e 100644
--- a/Src/Zle/zle.h
+++ b/Src/Zle/zle.h
@@ -186,7 +186,7 @@ typedef struct thingy *Thingy;
 
 /* widgets (ZLE functions) */
 
-typedef int (*ZleIntFunc) _((char **));
+typedef int (*ZleIntFunc) (char **);
 
 struct widget {
     int flags;		/* flags (see below) */
@@ -319,7 +319,7 @@ struct vichange {
 
 typedef struct keymap *Keymap;
 
-typedef void (*KeyScanFunc) _((char *, Thingy, char *, void *));
+typedef void (*KeyScanFunc) (char *, Thingy, char *, void *);
 
 #define invicmdmode() (!strcmp(curkeymapname, "vicmd"))
 
diff --git a/Src/Zle/zle_keymap.c b/Src/Zle/zle_keymap.c
index 041682ee9..5012917f5 100644
--- a/Src/Zle/zle_keymap.c
+++ b/Src/Zle/zle_keymap.c
@@ -745,7 +745,7 @@ bin_bindkey(char *name, char **argv, Options ops, UNUSED(int func))
     static struct opn {
 	char o;
 	char selp;
-	int (*func) _((char *, char *, Keymap, char **, Options, char));
+	int (*func) (char *, char *, Keymap, char **, Options, char);
 	int min, max;
     } const opns[] = {
 	{ 'l', 0, bin_bindkey_lsmaps, 0,  -1 },
diff --git a/Src/Zle/zle_thingy.c b/Src/Zle/zle_thingy.c
index 1b036a8a0..f71435b01 100644
--- a/Src/Zle/zle_thingy.c
+++ b/Src/Zle/zle_thingy.c
@@ -344,7 +344,7 @@ bin_zle(char *name, char **args, Options ops, UNUSED(int func))
 {
     static struct opn {
 	char o;
-	int (*func) _((char *, char **, Options, char));
+	int (*func) (char *, char **, Options, char);
 	int min, max;
     } const opns[] = {
 	{ 'l', bin_zle_list, 0, -1 },
diff --git a/Src/exec.c b/Src/exec.c
index 0231bc361..e955e85df 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -267,7 +267,7 @@ static char *blank_env[] = { NULL };
 
 /* Execution functions. */
 
-static int (*execfuncs[WC_COUNT-WC_CURSH]) _((Estate, int)) = {
+static int (*execfuncs[WC_COUNT-WC_CURSH]) (Estate, int) = {
     execcursh, exectime, NULL /* execfuncdef handled specially */,
     execfor, execselect,
     execwhile, execrepeat, execcase, execif, execcond,
diff --git a/Src/glob.c b/Src/glob.c
index bd199ace3..3e34f708e 100644
--- a/Src/glob.c
+++ b/Src/glob.c
@@ -133,7 +133,7 @@ typedef struct stat *Statptr;	 /* This makes the Ultrix compiler happy.  Go figu
 #define TT_TERABYTES 5
 
 
-typedef int (*TestMatchFunc) _((char *, struct stat *, off_t, char *));
+typedef int (*TestMatchFunc) (char *, struct stat *, off_t, char *);
 
 struct qual {
     struct qual *next;		/* Next qualifier, must match                */
@@ -1264,7 +1264,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 	int sense, qualsfound;
 	off_t data;
 	char *sdata, *newcolonmod, *ptr;
-	int (*func) _((char *, Statptr, off_t, char *));
+	int (*func) (char *, Statptr, off_t, char *);
 
 	/*
 	 * Initialise state variables for current file pattern.
@@ -1310,7 +1310,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 	    if (*ptr == Dash)
 		*ptr = '-';
 	while (*s && !newcolonmod) {
-	    func = (int (*) _((char *, Statptr, off_t, char *)))0;
+	    func = (int (*) (char *, Statptr, off_t, char *)) 0;
 	    if (*s == ',') {
 		/* A comma separates alternative sets of qualifiers */
 		s++;
@@ -1961,7 +1961,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 	/* Sort arguments in to lexical (and possibly numeric) order. *
 	 * This is reversed to facilitate insertion into the list.    */
 	qsort((void *) & matchbuf[0], matchct, sizeof(struct gmatch),
-	      (int (*) _((const void *, const void *)))gmatchcmp);
+	      (int (*) (const void *, const void *)) gmatchcmp);
     }
 
     if (first < 0) {
diff --git a/Src/hist.c b/Src/hist.c
index 448dfddbc..1a00c30ed 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -34,25 +34,25 @@
  * word control. */
 
 /**/
-mod_export int (*hgetc) _((void));
+mod_export int (*hgetc) (void);
 
 /**/
-void (*hungetc) _((int));
+void (*hungetc) (int);
 
 /**/
-void (*hwaddc) _((int));
+void (*hwaddc) (int);
 
 /**/
-void (*hwbegin) _((int));
+void (*hwbegin) (int);
 
 /**/
-void (*hwabort) _((void));
+void (*hwabort) (void);
 
 /**/
-void (*hwend) _((void));
+void (*hwend) (void);
 
 /**/
-void (*addtoline) _((int));
+void (*addtoline) (int);
 
 /* != 0 means history substitution is turned off */
  
diff --git a/Src/makepro.awk b/Src/makepro.awk
index 0d53c5850..56c4f4595 100644
--- a/Src/makepro.awk
+++ b/Src/makepro.awk
@@ -131,8 +131,8 @@ BEGIN {
 		sub(/@-.*$/, "", dnam)
 
 		# Put parens etc. back
-		gsub(/@[{]/, " _((", dcltor)
-		gsub(/@}/, "))", dcltor)
+		gsub(/@[{]/, " (", dcltor)
+		gsub(/@}/, ")", dcltor)
 		gsub(/@</, "(", dcltor)
 		gsub(/@>/, ")", dcltor)
 		gsub(/@!/, ",", dcltor)
diff --git a/Src/mem.c b/Src/mem.c
index fb4be47bf..0b6f76e46 100644
--- a/Src/mem.c
+++ b/Src/mem.c
@@ -1057,17 +1057,17 @@ zrealloc(void *ptr, size_t size)
 #if !defined(__hpux) && !defined(DGUX) && !defined(__osf__)
 # if defined(_BSD)
 #  ifndef HAVE_BRK_PROTO
-   extern int brk _((caddr_t));
+   extern int brk (caddr_t);
 #  endif
 #  ifndef HAVE_SBRK_PROTO
-   extern caddr_t sbrk _((int));
+   extern caddr_t sbrk (int);
 #  endif
 # else
 #  ifndef HAVE_BRK_PROTO
-   extern int brk _((void *));
+   extern int brk (void *);
 #  endif
 #  ifndef HAVE_SBRK_PROTO
-   extern void *sbrk _((int));
+   extern void *sbrk (int);
 #  endif
 # endif
 #endif
diff --git a/Src/mkbltnmlst.sh b/Src/mkbltnmlst.sh
index 067ecdaf9..1994ace60 100644
--- a/Src/mkbltnmlst.sh
+++ b/Src/mkbltnmlst.sh
@@ -122,12 +122,12 @@ for bin_mod in $bin_mods; do
 	esac
     done
     echo "    {"
-    echo "        extern int setup_${q_bin_mod} _((Module));"
-    echo "        extern int boot_${q_bin_mod} _((Module));"
-    echo "        extern int features_${q_bin_mod} _((Module,char***));"
-    echo "        extern int enables_${q_bin_mod} _((Module,int**));"
-    echo "        extern int cleanup_${q_bin_mod} _((Module));"
-    echo "        extern int finish_${q_bin_mod} _((Module));"
+    echo "        extern int setup_${q_bin_mod} (Module);"
+    echo "        extern int boot_${q_bin_mod} (Module);"
+    echo "        extern int features_${q_bin_mod} (Module,char***);"
+    echo "        extern int enables_${q_bin_mod} (Module,int**);"
+    echo "        extern int cleanup_${q_bin_mod} (Module);"
+    echo "        extern int finish_${q_bin_mod} (Module);"
     echo
     echo "        register_module(\"$bin_mod\","
     echo "                        setup_${q_bin_mod},"
diff --git a/Src/modentry.c b/Src/modentry.c
index 4d8217f43..23c499d94 100644
--- a/Src/modentry.c
+++ b/Src/modentry.c
@@ -1,10 +1,10 @@
 #include "zsh.mdh"
 
-int setup_ _((Module));
-int boot_ _((Module));
-int cleanup_ _((Module));
-int finish_ _((Module));
-int modentry _((int boot, Module m, void *ptr));
+int setup_ (Module);
+int boot_ (Module);
+int cleanup_ (Module);
+int finish_ (Module);
+int modentry (int boot, Module m, void *ptr);
 
 /**/
 int
diff --git a/Src/parse.c b/Src/parse.c
index 40eb0ee0b..334365649 100644
--- a/Src/parse.c
+++ b/Src/parse.c
@@ -2392,7 +2392,7 @@ par_nl_wordlist(void)
  */
 
 /**/
-void (*condlex) _((void)) = zshlex;
+void (*condlex) (void) = zshlex;
 
 /*
  * cond	: cond_1 { SEPER } [ DBAR { SEPER } cond ]
diff --git a/Src/prototypes.h b/Src/prototypes.h
index e3db4f5ee..3578482d0 100644
--- a/Src/prototypes.h
+++ b/Src/prototypes.h
@@ -28,9 +28,9 @@
  */
 
 #ifndef HAVE_STDLIB_H
-char *malloc _((size_t));
-char *realloc _((void *, size_t));
-char *calloc _((size_t, size_t));
+char *malloc (size_t);
+char *realloc (void *, size_t);
+char *calloc (size_t, size_t);
 #endif
 
 #if !(defined(USES_TERMCAP_H) || defined(USES_TERM_H))
@@ -45,11 +45,11 @@ char *calloc _((size_t, size_t));
 #else
 #define TC_CONST
 #endif
-extern int tgetent _((char *bp, TC_CONST char *name));
-extern int tgetnum _((char *id));
-extern int tgetflag _((char *id));
-extern char *tgetstr _((char *id, char **area));
-extern int tputs _((TC_CONST char *cp, int affcnt, int (*outc) (int)));
+extern int tgetent (char *bp, TC_CONST char *name);
+extern int tgetnum (char *id);
+extern int tgetflag (char *id);
+extern char *tgetstr (char *id, char **area);
+extern int tputs (TC_CONST char *cp, int affcnt, int (*outc) (int));
 #undef TC_CONST
 #endif
 
@@ -70,30 +70,30 @@ char *tgoto(const char *cap, int col, int row);
 #endif
 
 #ifdef __osf__
-char *mktemp _((char *));
+char *mktemp (char *);
 #endif
 
 #if defined(__osf__) && defined(__alpha) && defined(__GNUC__)
 /* Digital cc does not need these prototypes, gcc does need them */
 # ifndef HAVE_IOCTL_PROTO
-int ioctl _((int d, unsigned long request, void *argp));
+int ioctl (int d, unsigned long request, void *argp);
 # endif
 # ifndef HAVE_MKNOD_PROTO
-int mknod _((const char *pathname, int mode, dev_t device));
+int mknod (const char *pathname, int mode, dev_t device);
 # endif
-int nice _((int increment));
-int select _((int nfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds, struct timeval *timeout));
+int nice (int increment);
+int select (int nfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds, struct timeval *timeout);
 #endif
 
 #if defined(DGUX) && defined(__STDC__)
 /* Just plain missing. */
-extern int getrlimit _((int resource, struct rlimit *rlp));
-extern int setrlimit _((int resource, const struct rlimit *rlp));
-extern int getrusage _((int who, struct rusage *rusage));
-extern int gettimeofday _((struct timeval *tv, struct timezone *tz));
-extern int wait3 _((union wait *wait_status, int options, struct rusage *rusage));
-extern int getdomainname _((char *name, int maxlength));
-extern int select _((int nfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds, struct timeval *timeout));
+extern int getrlimit (int resource, struct rlimit *rlp);
+extern int setrlimit (int resource, const struct rlimit *rlp);
+extern int getrusage (int who, struct rusage *rusage);
+extern int gettimeofday (struct timeval *tv, struct timezone *tz);
+extern int wait3 (union wait *wait_status, int options, struct rusage *rusage);
+extern int getdomainname (char *name, int maxlength);
+extern int select (int nfds, fd_set * readfds, fd_set * writefds, fd_set * exceptfds, struct timeval *timeout);
 #endif /* DGUX and __STDC__ */
 
 #ifdef __NeXT__
@@ -101,34 +101,34 @@ extern pid_t getppid(void);
 #endif
 
 #if defined(__sun__) && !defined(__SVR4)  /* SunOS */
-extern char *strerror _((int errnum));
+extern char *strerror (int errnum);
 #endif
 
 /**************************************************/
 /*** prototypes for functions built in compat.c ***/
 #ifndef HAVE_STRSTR
-extern char *strstr _((const char *s, const char *t));
+extern char *strstr (const char *s, const char *t);
 #endif
 
 #ifndef HAVE_GETHOSTNAME
-extern int gethostname _((char *name, size_t namelen));
+extern int gethostname (char *name, size_t namelen);
 #endif
 
 #ifndef HAVE_GETTIMEOFDAY
-extern int gettimeofday _((struct timeval *tv, struct timezone *tz));
+extern int gettimeofday (struct timeval *tv, struct timezone *tz);
 #endif
 
 #ifndef HAVE_DIFFTIME
-extern double difftime _((time_t t2, time_t t1));
+extern double difftime (time_t t2, time_t t1);
 #endif
 
 #ifndef HAVE_STRERROR
-extern char *strerror _((int errnum));
+extern char *strerror (int errnum);
 #endif
 
 /*** end of prototypes for functions in compat.c ***/
 /***************************************************/
 
 #ifndef HAVE_MEMMOVE
-extern void bcopy _((const void *, void *, size_t));
+extern void bcopy (const void *, void *, size_t);
 #endif
diff --git a/Src/signals.h b/Src/signals.h
index 391f11fed..7910f6b79 100644
--- a/Src/signals.h
+++ b/Src/signals.h
@@ -27,7 +27,7 @@
  *
  */
 
-#define SIGNAL_HANDTYPE void (*)_((int))
+#define SIGNAL_HANDTYPE void (*)(int)
 
 #ifndef HAVE_KILLPG
 # define killpg(pgrp,sig) kill(-(pgrp),sig)
@@ -145,7 +145,7 @@
 #ifdef BSD_SIGNALS
 #define signal_block(S) sigblock(S)
 #else
-extern sigset_t signal_block _((sigset_t));
+extern sigset_t signal_block (sigset_t);
 #endif  /* BSD_SIGNALS   */
 
-extern sigset_t signal_unblock _((sigset_t));
+extern sigset_t signal_unblock (sigset_t);
diff --git a/Src/utils.c b/Src/utils.c
index c8831c85e..ce4e875fd 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -5277,6 +5277,7 @@ nicedupstring(char const *s)
 }
 
 
+/**/
 #ifndef MULTIBYTE_SUPPORT
 /* Unmetafy and output a string, displaying special characters readably. */
 
@@ -5311,8 +5312,9 @@ niceztrlen(char const *s)
     }
     return l;
 }
-#endif
 
+/**/
+#endif
 
 /**/
 #ifdef MULTIBYTE_SUPPORT
@@ -7633,6 +7635,7 @@ mode_to_octal(mode_t mode)
     return m;
 }
 
+/**/
 #ifdef MAILDIR_SUPPORT
 /*
  *     Stat a file. If it's a maildir, check all messages
@@ -7756,4 +7759,6 @@ mailstat(char *path, struct stat *st)
        *st = st_ret_last = st_ret;
        return 0;
 }
+
+/**/
 #endif
diff --git a/Src/zsh.h b/Src/zsh.h
index fae62b8d0..090abf8f5 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -618,7 +618,7 @@ union linkroot {
 /* Specific elements of linked lists */
 /*************************************/
 
-typedef void (*voidvoidfnptr_t) _((void));
+typedef void (*voidvoidfnptr_t) (void);
 
 /*
  * Element of the prepromptfns list.
@@ -678,7 +678,7 @@ struct timedfn {
 #define COND_MOD   18
 #define COND_MODI  19
 
-typedef int (*CondHandler) _((char **, int));
+typedef int (*CondHandler) (char **, int);
 
 struct conddef {
     Conddef next;		/* next in list                       */
@@ -1164,28 +1164,28 @@ struct dirsav {
 /* Definitions for Hash Tables */
 /*******************************/
 
-typedef void *(*VFunc) _((void *));
-typedef void (*FreeFunc) _((void *));
+typedef void *(*VFunc) (void *);
+typedef void (*FreeFunc) (void *);
 
-typedef unsigned (*HashFunc)       _((const char *));
-typedef void     (*TableFunc)      _((HashTable));
+typedef unsigned (*HashFunc)       (const char *);
+typedef void     (*TableFunc)      (HashTable);
 /*
  * Note that this is deliberately "char *", not "const char *",
  * since the AddNodeFunc is passed a pointer to a string that
  * will be stored and later freed.
  */
-typedef void     (*AddNodeFunc)    _((HashTable, char *, void *));
-typedef HashNode (*GetNodeFunc)    _((HashTable, const char *));
-typedef HashNode (*RemoveNodeFunc) _((HashTable, const char *));
-typedef void     (*FreeNodeFunc)   _((HashNode));
-typedef int      (*CompareFunc)    _((const char *, const char *));
+typedef void     (*AddNodeFunc)    (HashTable, char *, void *);
+typedef HashNode (*GetNodeFunc)    (HashTable, const char *);
+typedef HashNode (*RemoveNodeFunc) (HashTable, const char *);
+typedef void     (*FreeNodeFunc)   (HashNode);
+typedef int      (*CompareFunc)    (const char *, const char *);
 
 /* type of function that is passed to *
  * scanhashtable or scanmatchtable    */
-typedef void     (*ScanFunc)       _((HashNode, int));
-typedef void     (*ScanTabFunc)    _((HashTable, ScanFunc, int));
+typedef void     (*ScanFunc)       (HashNode, int);
+typedef void     (*ScanTabFunc)    (HashTable, ScanFunc, int);
 
-typedef void (*PrintTableStats) _((HashTable));
+typedef void (*PrintTableStats) (HashTable);
 
 /* Hash table for standard open hashing. Instances of struct hashtable can be *
  * created only by newhashtable(). In fact, this function creates an instance *
@@ -1352,7 +1352,7 @@ struct funcstack {
 
 /* node in list of function call wrappers */
 
-typedef int (*WrapFunc) _((Eprog, FuncWrap, char *));
+typedef int (*WrapFunc) (Eprog, FuncWrap, char *);
 
 struct funcwrap {
     FuncWrap next;
@@ -1428,8 +1428,8 @@ enum {
  * builtin structure.
  */
 
-typedef int (*HandlerFunc) _((char *, char **, Options, int));
-typedef int (*HandlerFuncAssign) _((char *, char **, LinkList, Options, int));
+typedef int (*HandlerFunc) (char *, char **, Options, int);
+typedef int (*HandlerFuncAssign) (char *, char **, LinkList, Options, int);
 #define NULLBINCMD ((HandlerFunc) 0)
 
 struct builtin {
@@ -1526,10 +1526,10 @@ struct module {
 /* Module record is an alias */
 #define MOD_ALIAS   (1<<6)
 
-typedef int (*Module_generic_func) _((void));
-typedef int (*Module_void_func) _((Module));
-typedef int (*Module_features_func) _((Module, char ***));
-typedef int (*Module_enables_func) _((Module, int **));
+typedef int (*Module_generic_func) (void);
+typedef int (*Module_void_func) (Module);
+typedef int (*Module_features_func) (Module, char ***);
+typedef int (*Module_enables_func) (Module, int **);
 
 struct linkedmod {
     char *name;
@@ -1574,7 +1574,7 @@ struct feature_enables {
 
 /* C-function hooks */
 
-typedef int (*Hookfn) _((Hookdef, void *));
+typedef int (*Hookfn) (Hookdef, void *);
 
 struct hookdef {
     Hookdef next;
@@ -1789,33 +1789,33 @@ typedef const struct gsu_array *GsuArray;
 typedef const struct gsu_hash *GsuHash;
 
 struct gsu_scalar {
-    char *(*getfn) _((Param));
-    void (*setfn) _((Param, char  *));
-    void (*unsetfn) _((Param, int));
+    char *(*getfn) (Param);
+    void (*setfn) (Param, char  *);
+    void (*unsetfn) (Param, int);
 };
 
 struct gsu_integer {
-    zlong (*getfn) _((Param));
-    void (*setfn) _((Param, zlong));
-    void (*unsetfn) _((Param, int));
+    zlong (*getfn) (Param);
+    void (*setfn) (Param, zlong);
+    void (*unsetfn) (Param, int);
 };
 
 struct gsu_float {
-    double (*getfn) _((Param));
-    void (*setfn) _((Param, double));
-    void (*unsetfn) _((Param, int));
+    double (*getfn) (Param);
+    void (*setfn) (Param, double);
+    void (*unsetfn) (Param, int);
 };
 
 struct gsu_array {
-    char **(*getfn) _((Param));
-    void (*setfn) _((Param, char **));
-    void (*unsetfn) _((Param, int));
+    char **(*getfn) (Param);
+    void (*setfn) (Param, char **);
+    void (*unsetfn) (Param, int);
 };
 
 struct gsu_hash {
-    HashTable (*getfn) _((Param));
-    void (*setfn) _((Param, HashTable));
-    void (*unsetfn) _((Param, int));
+    HashTable (*getfn) (Param);
+    void (*setfn) (Param, HashTable);
+    void (*unsetfn) (Param, int);
 };
 
 
@@ -2984,7 +2984,7 @@ enum errflag_bits {
 /* Sorting */
 /***********/
 
-typedef int (*CompareFn) _((const void *, const void *));
+typedef int (*CompareFn) (const void *, const void *);
 
 enum {
     SORTIT_ANYOLDHOW = 0,	/* Defaults */
@@ -3042,13 +3042,13 @@ struct hist_stack {
     short *chwords;
     int chwordlen;
     int chwordpos;
-    int (*hgetc) _((void));
-    void (*hungetc) _((int));
-    void (*hwaddc) _((int));
-    void (*hwbegin) _((int));
-    void (*hwabort) _((void));
-    void (*hwend) _((void));
-    void (*addtoline) _((int));
+    int (*hgetc) (void);
+    void (*hungetc) (int);
+    void (*hwaddc) (int);
+    void (*hwbegin) (int);
+    void (*hwabort) (void);
+    void (*hwend) (void);
+    void (*addtoline) (int);
     unsigned char *cstack;
     int csp;
     int hist_keep_comment;
@@ -3218,7 +3218,7 @@ enum {
 
 /* compctl entry point pointers */
 
-typedef int (*CompctlReadFn) _((char *, char **, Options, char *));
+typedef int (*CompctlReadFn) (char *, char **, Options, char *);
 
 /* ZLE entry point pointer */
 
diff --git a/Src/zsh_system.h b/Src/zsh_system.h
index 16f724401..5c004d53e 100644
--- a/Src/zsh_system.h
+++ b/Src/zsh_system.h
@@ -82,12 +82,6 @@
  */
 #define _STRPTIME_DONTZERO
 
-#ifdef PROTOTYPES
-# define _(Args) Args
-#else
-# define _(Args) ()
-#endif
-
 #ifndef HAVE_ALLOCA
 # define alloca zhalloc
 #else
@@ -101,7 +95,7 @@
  #   pragma alloca
 #   else
 #    ifndef alloca
-char *alloca _((size_t));
+char *alloca (size_t);
 #    endif
 #   endif
 #  endif
diff --git a/aclocal.m4 b/aclocal.m4
index c26e2d834..792d533f2 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -2,56 +2,6 @@
 # Copyright (C) 1992, 1994 Free Software Foundation, Inc.
 # Francois Pinard <pinard@iro.umontreal.ca>, 1992.
 
-# @defmac fp_PROG_CC_STDC
-# @maindex PROG_CC_STDC
-# @ovindex CC
-# If the C compiler in not in ANSI C mode by default, try to add an option
-# to output variable @code{CC} to make it so.  This macro tries various
-# options that select ANSI C on some system or another.  It considers the
-# compiler to be in ANSI C mode if it defines @code{__STDC__} to 1 and
-# handles function prototypes correctly.
-# 
-# If you use this macro, you should check after calling it whether the C
-# compiler has been set to accept ANSI C; if not, the shell variable
-# @code{fp_cv_prog_cc_stdc} is set to @samp{no}.  If you wrote your source
-# code in ANSI C, you can make an un-ANSIfied copy of it by using the
-# program @code{ansi2knr}, which comes with Ghostscript.
-# @end defmac
-
-define(fp_PROG_CC_STDC,
-[AC_CACHE_CHECK(for ${CC-cc} option to accept ANSI C,
-fp_cv_prog_cc_stdc,
-[fp_cv_prog_cc_stdc=no
-ac_save_CFLAGS="$CFLAGS"
-# Don't try gcc -ansi; that turns off useful extensions and
-# breaks some systems' header files.
-# AIX			-qlanglvl=ansi
-# Ultrix and OSF/1	-std1
-# HP-UX			-Ae  or  -Aa -D_HPUX_SOURCE
-# SVR4			-Xc
-#  For HP-UX, we try -Ae first; this turns on ANSI but also extensions,
-#  as well as defining _HPUX_SOURCE, and we can then use long long.
-#  We keep the old version for backward compatibility.
-for ac_arg in "" -qlanglvl=ansi -std1 -Ae "-Aa -D_HPUX_SOURCE" -Xc
-do
-  CFLAGS="$ac_save_CFLAGS $ac_arg"
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
-[#ifndef __STDC__
-choke me
-#endif	
-]], [[int test (int i, double x);
-struct s1 {int (*f) (int a);};
-struct s2 {int (*f) (double a);};]])],
-[fp_cv_prog_cc_stdc="$ac_arg"; break],[])
-done
-CFLAGS="$ac_save_CFLAGS"
-])
-case "x$fp_cv_prog_cc_stdc" in
-  x|xno) ;;
-  *) CC="$CC $fp_cv_prog_cc_stdc" ;;
-esac
-])
-
 AC_DEFUN(AC_PROG_LN,
 [AC_MSG_CHECKING(whether ln works)
 AC_CACHE_VAL(ac_cv_prog_LN,
diff --git a/configure.ac b/configure.ac
index 175d90433..ba3f2fe90 100644
--- a/configure.ac
+++ b/configure.ac
@@ -273,11 +273,6 @@ fi],
 AC_DEFINE(CONFIG_LOCALE)
 )
 
-dnl Do you want to compile as K&R C.
-AC_ARG_ENABLE(ansi2knr,
-AS_HELP_STRING([--enable-ansi2knr],[translate source to K&R C before compiling]),
-[ansi2knr="$enableval"], [ansi2knr=default])
-
 ifdef([runhelpdir],[undefine([runhelpdir])])dnl
 AC_ARG_ENABLE(runhelpdir,
 AS_HELP_STRING([--enable-runhelpdir=DIR],[the directory in which to install run-help files]),
@@ -483,7 +478,7 @@ fi
 dnl if the user hasn't specified CFLAGS, then
 dnl   if compiler is gcc, then use -O2 and some warning flags
 dnl   else use -O
-if test -n "$auto_cflags" && test ."$ansi2knr" != .yes; then
+if test -n "$auto_cflags"; then
   if test "${enable_zsh_debug}" = yes; then
     if test -n "$GCC"; then
       CFLAGS="$CFLAGS -Wall -Wmissing-prototypes -ggdb"
@@ -558,28 +553,6 @@ case "$host_os" in
 esac
 
 fp_PROG_CC_STDC
-AC_MSG_CHECKING([whether to use prototypes])
-if test ."$ansi2knr" = .yes || test ."$ansi2knr" = .no; then
-  msg="(overridden) "
-else
-  msg=
-  if test ."$fp_cv_prog_cc_stdc" = .no; then
-    ansi2knr=yes
-  else
-    ansi2knr=no
-  fi
-fi
-AH_TEMPLATE([PROTOTYPES],
-[Define to 1 if ANSI function prototypes are usable.])
-if test "$ansi2knr" = yes; then
-  AC_MSG_RESULT(${msg}no)
-  U=_
-else
-  AC_MSG_RESULT(${msg}yes)
-  AC_DEFINE(PROTOTYPES)
-  U=
-fi
-AC_SUBST(U)
 
 AC_FUNC_ALLOCA              dnl Check how to get `alloca'.
 
@@ -647,18 +620,6 @@ case "$LC_PAPER" in
 esac
 AC_SUBST(PAPERSIZE)
 
-AC_CHECK_PROGS([ANSI2KNR], [ansi2knr], [: ansi2knr])
-
-if test x"$ansi2knr" = xyes && test x"$ANSI2KNR" = x": ansi2knr"; then
-    echo "----------"
-    echo "configure fatal error:"
-    echo "ansi2knr was specified (--enable-ansi2knr) but the program could not be found."
-    echo "Either remove the configure option if it is not required or build the ansi2knr"
-    echo "program before reconfiguring Zsh.  The source code for ansi2knr is also"
-    echo "available in the GPL directory on Zsh distribution sites."
-    exit 1
-fi
-
 dnl ------------------
 dnl CHECK HEADER FILES
 dnl ------------------

Re: ANSI C standard of zsh

[Clinton Bunch]

On 3/13/2024 11:49, Oliver Kiddle wrote:
> Bart Schaefer wrote:
>> On Tue, Mar 12, 2024 at 2:44 PM Clinton Bunch <cdb_zsh@zentaur.org> wrote:
>>>   I propose that we update the development guide to remove the bit about the 1989 standard (much less K&R compatibility) since it is no longer true, and I personally question if it even makes sense as a goal 30+ years in to development.
> No objections from me. Replacement wording would be welcome. We're using
> string pasting (##) in quite a few places despite that being "not
> available".
>
Here is my first cut at replacement wording for the first two paragraphs 
of the C coding style section:

The primary language is standard C and modern versions of Zsh assume at 
least the 1999 standard is available.  While much of the code is written 
to be compatible with older C standards, it has been decided that 
maintaining compatibility with those standards has become too limiting 
and is not necessary for even legacy (though not necessarily vintage) 
systems.

If you wish to use features not present in the ANSI C 99 standard, there 
are preprocessor macros to provide safe access to some of these.  Always 
use the macros if you want to use these facilities.

Re: ANSI C standard of zsh

[Oliver Kiddle]

Clinton Bunch wrote:
> Here is my first cut at replacement wording for the first two paragraphs 
> of the C coding style section:

This looks good to me.

> If you wish to use features not present in the ANSI C 99 standard, there 
> are preprocessor macros to provide safe access to some of these.  Always 
> use the macros if you want to use these facilities.

I was trying to think how this reads to someone completely unfamiliar
with the zsh code and what macros we have that meet this description.
Autoconf detects mostly system library/OS features and the macros
related to that are either defined to 1 (or left undefined). So the
macros allow you to make the use of such features conditional. "provide
safe access" sounds more like a wrapper – I couldn't think of an
example but that's not to say there aren't any. The preprocessor macros
are for anything that isn't portable rather than a particular language
standard.

Oliver

Re: ANSI C standard of zsh

[Clinton Bunch]

On 3/25/2024 18:47, Oliver Kiddle wrote:
> Clinton Bunch wrote:
>> Here is my first cut at replacement wording for the first two paragraphs
>> of the C coding style section:
> This looks good to me.
>
>> If you wish to use features not present in the ANSI C 99 standard, there
>> are preprocessor macros to provide safe access to some of these.  Always
>> use the macros if you want to use these facilities.
> I was trying to think how this reads to someone completely unfamiliar
> with the zsh code and what macros we have that meet this description.
> Autoconf detects mostly system library/OS features and the macros
> related to that are either defined to 1 (or left undefined). So the
> macros allow you to make the use of such features conditional. "provide
> safe access" sounds more like a wrapper – I couldn't think of an
> example but that's not to say there aren't any. The preprocessor macros
> are for anything that isn't portable rather than a particular language
> standard.
>
> Oliver
I think what was intended was macros like _POSIX_C_SOURCE and 
_XOPEN_SOURCE and __STDC__.  The glibc man pages are littered with them.

Re: ANSI C standard of zsh

[Clinton Bunch]

[-- Attachment #1: Type: text/plain, Size: 1436 bytes --]

On 3/25/2024 19:32, Clinton Bunch wrote:
> On 3/25/2024 18:47, Oliver Kiddle wrote:
>> Clinton Bunch wrote:
>>> Here is my first cut at replacement wording for the first two 
>>> paragraphs
>>> of the C coding style section:
>> This looks good to me.
>>
>>> If you wish to use features not present in the ANSI C 99 standard, 
>>> there
>>> are preprocessor macros to provide safe access to some of these.  
>>> Always
>>> use the macros if you want to use these facilities.
>> I was trying to think how this reads to someone completely unfamiliar
>> with the zsh code and what macros we have that meet this description.
>> Autoconf detects mostly system library/OS features and the macros
>> related to that are either defined to 1 (or left undefined). So the
>> macros allow you to make the use of such features conditional. "provide
>> safe access" sounds more like a wrapper – I couldn't think of an
>> example but that's not to say there aren't any. The preprocessor macros
>> are for anything that isn't portable rather than a particular language
>> standard.
>>
>> Oliver
> I think what was intended was macros like _POSIX_C_SOURCE and 
> _XOPEN_SOURCE and __STDC__.  The glibc man pages are littered with them.
>
>
If we're going to say Zsh expects C99 we should probably update autoconf 
to check for C99 (and set any options needed)

I've attached a patch for the trivial change needed.



[-- Attachment #2: zsh-autoconf-c99.patch.txt --]
[-- Type: text/plain, Size: 383 bytes --]

diff --git a/configure.ac b/configure.ac
index 78621042d..5984b667e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -462,7 +462,7 @@ dnl We want these before the checks, so the checks can modify their values.
 test -z "${CFLAGS+set}"  && CFLAGS=  auto_cflags=1
 test -z "${LDFLAGS+set}" && LDFLAGS= auto_ldflags=1
 
-AC_PROG_CC
+AC_PROG_CC_C99
 
 dnl Check for large file support.
 

Re: ANSI C standard of zsh

[Jun T]

> 2024/03/27 8:16、Clinton Bunch <cdb_zsh@zentaur.org>のメール:
> 
> If we're going to say Zsh expects C99 we should probably update
> autoconf to check for C99 (and set any options needed)
> 
> I've attached a patch for the trivial change needed.
in the attached patch:
> -AC_PROG_CC
> +AC_PROG_CC_C99

We can use AC_PROG_CC_C99 with autoconf-2.69, but in 2.7x
it became obsolete and we need to use AC_PROG_CC, which
tries C11, C99 and C89 (in this order) to find the latest
edition the compiler supports.

So we first need to decide which version of autoconf we
use. Maybe we will continue using 2.69 for the moment?


The following is info for someone who wants to know
what AC_PROG_CC_C99 will check.
In the comment to the AC_PROG_CC_C99 macro in c.m4
(may be in /usr/share/autoconf/autoconf/ if you have 2.69
installed, or lib/autoconf/ in the autoconf source tree):

# It (AC_PROG_CC_C99) considers the compiler to be in ISO C99
# mode if it handles
# _Bool,
# // comments,
# flexible array members,          # aka incomplete array
# inline,
# long long int,
# mixed code and declarations,
# named initialization of structs, # aka designated initializer
# restrict,
# va_copy,                  # with <stdarg.h> and va_start etc.
# varargs macros,        # macros with variable number of args
# variable declarations in for loops      # for(int i=0; ...)
# variable length arrays

Note that "variable length array" (optional in C11) is
required.

AC_PROG_CC_C99 does not check, for example (not comprehensive):
headers other than <stdarg.h>, i.e., <complex.h>, <stdbool.h>,
   <tgmath.h>, <intypes.h>, etc.
snprintf() (and any other new library functions)
universal character name: \uNNNN, \UNNNNNNNN
compound literal

Re: ANSI C standard of zsh

[Clinton Bunch]

On 3/28/2024 04:16, Jun T wrote:
>> 2024/03/27 8:16、Clinton Bunch <cdb_zsh@zentaur.org>のメール:
>>
>> If we're going to say Zsh expects C99 we should probably update
>> autoconf to check for C99 (and set any options needed)
>>
>> I've attached a patch for the trivial change needed.
> in the attached patch:
>> -AC_PROG_CC
>> +AC_PROG_CC_C99
> We can use AC_PROG_CC_C99 with autoconf-2.69, but in 2.7x
> it became obsolete and we need to use AC_PROG_CC, which
> tries C11, C99 and C89 (in this order) to find the latest
> edition the compiler supports.
>
> So we first need to decide which version of autoconf we
> use. Maybe we will continue using 2.69 for the moment?

EL 8 and 9 still ship 2.69, as does Solaris 11

FreeBSD 13.2-RELEASE-p10 has 2.71

The development guide currently says 2.50 or later.

2.71 is copyright 2021. 2.69 is 2012.

I believe in updating versions when they become too limiting, but 3 
years isn't what I'd consider limiting.  I don't think we should change 
to assume 2.71 yet.


Do we need to know that the compiler supports C11 unless we're using C11 
features?


>
>
> The following is info for someone who wants to know
> what AC_PROG_CC_C99 will check.
> In the comment to the AC_PROG_CC_C99 macro in c.m4
> (may be in /usr/share/autoconf/autoconf/ if you have 2.69
> installed, or lib/autoconf/ in the autoconf source tree):
>
> # It (AC_PROG_CC_C99) considers the compiler to be in ISO C99
> # mode if it handles
> # _Bool,
> # // comments,
> # flexible array members,          # aka incomplete array
> # inline,
> # long long int,
> # mixed code and declarations,
> # named initialization of structs, # aka designated initializer
> # restrict,
> # va_copy,                  # with <stdarg.h> and va_start etc.
> # varargs macros,        # macros with variable number of args
> # variable declarations in for loops      # for(int i=0; ...)
> # variable length arrays
>
> Note that "variable length array" (optional in C11) is
> required.
The current development guide specifically mentions support for variable 
length arrays.
>
> AC_PROG_CC_C99 does not check, for example (not comprehensive):
> headers other than <stdarg.h>, i.e., <complex.h>, <stdbool.h>,
>     <tgmath.h>, <intypes.h>, etc.
> snprintf() (and any other new library functions)
> universal character name: \uNNNN, \UNNNNNNNN
> compound literal
>

Re: ANSI C standard of zsh

[Vincent Lefevre]

On 2024-03-28 07:29:43 -0500, Clinton Bunch wrote:
> Do we need to know that the compiler supports C11 unless we're using
> C11 features?

Even if you are not using C11 features, GCC has some fixes only
in C11+ modes:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87390

I don't know whether zsh is concerned.

-- 
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)

Re: ANSI C standard of zsh

[Clinton Bunch]

On 4/3/2024 19:00, Vincent Lefevre wrote:
> On 2024-03-28 07:29:43 -0500, Clinton Bunch wrote:
>> Do we need to know that the compiler supports C11 unless we're using
>> C11 features?
> Even if you are not using C11 features, GCC has some fixes only
> in C11+ modes:
>
>    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87390
>
> I don't know whether zsh is concerned.


I would think if we needed to write alternate code for a C99 v C11 mode 
GCC it would be better to use __STDC__ and __GNUC__ macros rather than 
define a new macro in autoconf.

>