From ace5874aa41f07d1e3239a4ede58fc528de821d7 Mon Sep 17 00:00:00 2001
From: Karl Williamson <khw@cpan.org>
Date: Sat, 27 Dec 2025 19:37:15 -0700
Subject: [PATCH] Add Configure probe for size of intmax_t

Now that we require C99, we should be able to probe for this

Some internal operations can benefit from using the widest type possible
on the system, even if IVs and UVs don't use the full width.

This data is kept in <stdint.h>, which should always be available in
C99-compliant build systems.  Configure has a 'i_stdint', but it comes
much later in Configure than this does.  I tried moving it to earlier,
but then it relies on stuff that would have to get moved too, and I
think that stuff has to be later.

It gets complicated trying to deal with this value not existing, as
there is a separate unit for 'long long', which would have to be
considered.  Until and unless some platform comes along that this
doesn't work for, I just assume that this C99 construct will work as
expected.
---
 Configure                      | 11 ++++++++++-
 Cross/config.sh-arm-linux      |  1 +
 Cross/config.sh-arm-linux-n770 |  1 +
 Porting/Glossary               |  4 ++++
 Porting/config.sh              |  1 +
 config_h.SH                    |  5 +++++
 configure.com                  |  6 ++++++
 plan9/config_sh.sample         |  1 +
 win32/config.gc                |  1 +
 win32/config.vc                |  1 +
 10 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/Configure b/Configure
index ef2257f43838..27410e8f759c 100755
--- a/Configure
+++ b/Configure
@@ -1111,6 +1111,7 @@ installprefix=''
 installprefixexp=''
 installstyle=''
 installusrbinperl=''
+intmaxsize=''
 intsize=''
 longsize=''
 shortsize=''
@@ -5787,12 +5788,14 @@ case "$intsize" in
 #ifdef I_STDLIB
 #include <stdlib.h>
 #endif
+#include <stdint.h>
 #include <stdio.h>
 int main()
 {
 	printf("intsize=%d;\n", (int)sizeof(int));
 	printf("longsize=%d;\n", (int)sizeof(long));
 	printf("shortsize=%d;\n", (int)sizeof(short));
+	printf("intmaxsize=%d;\n", (int)sizeof(intmax_t));
 	exit(0);
 }
 EOCP
@@ -5802,6 +5805,7 @@ EOCP
 		echo "Your integers are $intsize bytes long."
 		echo "Your long integers are $longsize bytes long."
 		echo "Your short integers are $shortsize bytes long."
+		echo "Your longest integers are $intmaxsize bytes long."
 	else
 		$cat >&4 <<EOM
 !
@@ -5822,6 +5826,10 @@ EOM
 		rp="What is the size of a short integer (in bytes)?"
 		. ./myread
 		shortsize="$ans"
+		dflt=$longsize
+		rp="What is the size of a intmax_t integer (in bytes)?"
+		. ./myread
+		intmaxsize="$ans"
 	fi
 	;;
 esac
@@ -24264,7 +24272,7 @@ $rm_try
 set i_stdckdint
 eval $setvar
 
-: see if stdint is available
+: stdint.h should be available, but this makes sure it gets in config.h
 set stdint.h i_stdint
 eval $inhdr
 
@@ -25753,6 +25761,7 @@ installvendorlib='$installvendorlib'
 installvendorman1dir='$installvendorman1dir'
 installvendorman3dir='$installvendorman3dir'
 installvendorscript='$installvendorscript'
+intmaxsize='$intmaxsize'
 intsize='$intsize'
 issymlink='$issymlink'
 ivdformat='$ivdformat'
diff --git a/Cross/config.sh-arm-linux b/Cross/config.sh-arm-linux
index 0fcf0a0b4645..c43bfdeb936c 100644
--- a/Cross/config.sh-arm-linux
+++ b/Cross/config.sh-arm-linux
@@ -868,6 +868,7 @@ installvendorlib=''
 installvendorman1dir=''
 installvendorman3dir=''
 installvendorscript=''
+intmaxsize='8'
 intsize='4'
 issymlink='/usr/bin/test -h'
 ivdformat='"ld"'
diff --git a/Cross/config.sh-arm-linux-n770 b/Cross/config.sh-arm-linux-n770
index 18607ad0ff73..4621ecfb27b1 100644
--- a/Cross/config.sh-arm-linux-n770
+++ b/Cross/config.sh-arm-linux-n770
@@ -866,6 +866,7 @@ installvendorlib=''
 installvendorman1dir=''
 installvendorman3dir=''
 installvendorscript=''
+intmaxsize='8'
 intsize='4'
 issymlink='/usr/bin/test -h'
 ivdformat='"ld"'
diff --git a/Porting/Glossary b/Porting/Glossary
index abea6f9acb64..85e5823c3dc4 100644
--- a/Porting/Glossary
+++ b/Porting/Glossary
@@ -4134,6 +4134,10 @@ installvendorscript (vendorscript.U):
 	those systems using AFS. For extra portability, only this variable
 	should be used in makefiles.
 
+intmaxsize (intsize.U):
+	This variable contains the value of the INTMAXSIZE symbol, which
+	indicates to the C program how many bytes there are in intmax_t.
+
 intsize (intsize.U):
 	This variable contains the value of the INTSIZE symbol, which
 	indicates to the C program how many bytes there are in an int.
diff --git a/Porting/config.sh b/Porting/config.sh
index 41e0e490b3f0..b5390d68e037 100644
--- a/Porting/config.sh
+++ b/Porting/config.sh
@@ -892,6 +892,7 @@ installvendorlib=''
 installvendorman1dir=''
 installvendorman3dir=''
 installvendorscript=''
+intmaxsize='8'
 intsize='4'
 issymlink='test -h'
 ivdformat='"ld"'
diff --git a/config_h.SH b/config_h.SH
index 9f7082e9c614..124710fee389 100755
--- a/config_h.SH
+++ b/config_h.SH
@@ -799,9 +799,14 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
  *	This symbol contains the value of sizeof(short) so that the C
  *	preprocessor can make decisions based on it.
  */
+/* INTMAXSIZE:
+ *	This symbol contains the value of sizeof(intmax_t) so that the C
+ *	preprocessor can make decisions based on it.
+ */
 #define INTSIZE $intsize		/**/
 #define LONGSIZE $longsize		/**/
 #define SHORTSIZE $shortsize		/**/
+#define INTMAXSIZE $intmaxsize		/**/
 
 /* MULTIARCH:
  *	This symbol, if defined, signifies that the build
diff --git a/configure.com b/configure.com
index f800aecc6ea0..16ec73f2cf30 100644
--- a/configure.com
+++ b/configure.com
@@ -3263,6 +3263,7 @@ $ OS
 $ WS "#if defined(__DECC) || defined(__DECCXX)"
 $ WS "#include <stdlib.h>"
 $ WS "#endif"
+$ WS "#include <stdint.h>"
 $ WS "#include <stdio.h>"
 $ WS "int main()"
 $ WS "{"
@@ -5574,6 +5575,10 @@ $   gosub type_size_check
 $   intsize = tmp
 $ ENDIF
 $!
+$ tmp = "''intmax_t'"
+$ gosub type_size_check
+$ intmaxsize = tmp
+$!
 $ tmp = "''u32type'"
 $ gosub type_size_check
 $ u32size = tmp
@@ -6615,6 +6620,7 @@ $ WC "installsitearch='" + installsitearch + "'"
 $ WC "installsitebin='" + sitebin + "'"
 $ WC "installsitelib='" + installsitelib + "'"
 $ WC "installusrbinperl='undef'"
+$ WC "intmaxsize='" + intmaxsize + "'"
 $ WC "intsize='" + intsize + "'"
 $ WC "ivdformat='" + ivdformat + "'"
 $ WC "ivsize='" + ivsize + "'"
diff --git a/plan9/config_sh.sample b/plan9/config_sh.sample
index 3da90256ec4a..9b142bd8aab1 100644
--- a/plan9/config_sh.sample
+++ b/plan9/config_sh.sample
@@ -850,6 +850,7 @@ installusrbinperl='undef'
 installvendorarch=''
 installvendorbin=''
 installvendorlib=''
+intmaxsize='8'
 intsize='4'
 issymlink='/bin/test -h'
 ivdformat='"ld"'
diff --git a/win32/config.gc b/win32/config.gc
index 017c14d30abc..756fc2f406bc 100644
--- a/win32/config.gc
+++ b/win32/config.gc
@@ -862,6 +862,7 @@ installvendorlib=''
 installvendorman1dir=''
 installvendorman3dir=''
 installvendorscript=''
+intmaxsize='8'
 intsize='4'
 issymlink=''
 ivdformat='"ld"'
diff --git a/win32/config.vc b/win32/config.vc
index 77351781cdc7..b13e276ff74d 100644
--- a/win32/config.vc
+++ b/win32/config.vc
@@ -861,6 +861,7 @@ installvendorlib=''
 installvendorman1dir=''
 installvendorman3dir=''
 installvendorscript=''
+intmaxsize='8'
 intsize='4'
 issymlink=''
 ivdformat='"ld"'