From: Jarkko Hietaniemi <jhi@iki.fi>
Date: Thu, 17 Apr 2003 14:53:41 +0000 (+0000)
Subject: Small tidying up of the selectminbits code, but most
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=e6e7e605dfd1c8f7e052b3078d809836c27a2fc0;p=p5sagit%2Fp5-mst-13.2.git

Small tidying up of the selectminbits code, but most
importantly allocate the buffer from the heap using
malloc, not from the stack: using stack causes unaligned
access in LP64 Solaris since stack data is not guaranteed
to be 64-bit aligned, while a fd_set is (it has 1024 longs).
(via Alan Burlison)

p4raw-id: //depot/perl@19248
---

diff --git a/Configure b/Configure
index 5e3de68..14bba08 100755
--- a/Configure
+++ b/Configure
@@ -20,7 +20,7 @@
 
 # $Id: Head.U,v 3.0.1.9 1997/02/28 15:02:09 ram Exp $
 #
-# Generated on Wed Apr 16 12:35:41 EET DST 2003 [metaconfig 3.0 PL70]
+# Generated on Thu Apr 17 18:50:57 EET DST 2003 [metaconfig 3.0 PL70]
 # (with additional metaconfig patches by perlbug@perl.org)
 
 cat >c1$$ <<EOF
@@ -18673,7 +18673,8 @@ esac
 
 : check for the select 'width'
 case "$selectminbits" in
-'') case "$d_select" in
+'') safebits=`expr $ptrsize \* 8`
+    case "$d_select" in
 	$define)
 		$cat <<EOM
 
@@ -18715,19 +18716,21 @@ $selecttype b;
 #define NBYTES (S * 8 > MINBITS ? S : MINBITS/8)
 #define NBITS  (NBYTES * 8)
 int main() {
-    char s[NBYTES];
+    char *s = malloc(NBYTES);
     struct timeval t;
     int i;
     FILE* fp;
     int fd;
 
+    if (!s)
+	exit(1);
     fclose(stdin);
     fp = fopen("try.c", "r");
     if (fp == 0)
-      exit(1);
+      exit(2);
     fd = fileno(fp);
     if (fd < 0)
-      exit(2);
+      exit(3);
     b = ($selecttype)s;
     for (i = 0; i < NBITS; i++)
 	FD_SET(i, b);
@@ -18735,6 +18738,7 @@ int main() {
     t.tv_usec = 0;
     select(fd + 1, b, 0, 0, &t);
     for (i = NBITS - 1; i > fd && FD_ISSET(i, b); i--);
+    free(s);
     printf("%d\n", i + 1);
     return 0;
 }
@@ -18745,10 +18749,10 @@ EOCP
 			case "$selectminbits" in
 			'')	cat >&4 <<EOM
 Cannot figure out on how many bits at a time your select() operates.
-I'll play safe and guess it is 32 bits.
+I'll play safe and guess it is $safebits bits.
 EOM
-				selectminbits=32
-				bits="32 bits"
+				selectminbits=$safebits
+				bits="$safebits bits"
 				;;
 			1)	bits="1 bit" ;;
 			*)	bits="$selectminbits bits" ;;
@@ -18757,7 +18761,8 @@ EOM
 		else
 			rp='What is the minimum number of bits your select() operates on?'
 			case "$byteorder" in
-			1234|12345678)	dflt=32 ;;
+			12345678)	dflt=64 ;;
+			1234)		dflt=32 ;;
 			*)		dflt=1	;;
 			esac
 			. ./myread
@@ -18767,7 +18772,7 @@ EOM
 		$rm -f try.* try
 		;;
 	*)	: no select, so pick a harmless default
-		selectminbits='32'
+		selectminbits=$safebits
 		;;
 	esac
 	;;