Re: [Qemu-devel] patch: configure: nonstandard use of `expr'

[Juergen Lock]

In article <address@hidden> you write:
>Juergen Lock wrote:
>> At least FreeBSD's expr(1) doesnt understand the syntax now used in
>> configure:
>> 
>> Index: qemu/configure
>> @@ -157,7 +157,7 @@
>>  fi
>>  
>>  for opt do
>> -  optarg=`expr "$opt" : '[^=]*=\(.*\)'`
>> +  optarg=`echo "$opt" |sed 's/^[^=]*=//'`
>>    case "$opt" in
>>    --help|-h) show_help=yes
>>    ;;
>
>The GNU Autoconf manual, and its code, recommends something like this
>(note the "x" prefix):
>
>  optarg=`expr "x$opt" : 'x[^=]*=\(.*\)'`
>
>Your echo version suffers from non-portable results when opt matches "-n*",
>"-e*", "-E*", or something with a backslash in.

Oh, indeed.  Better version:

Index: qemu/configure
@@ -157,7 +157,7 @@
 fi
 
 for opt do
-  optarg=`expr "$opt" : '[^=]*=\(.*\)'`
+  optarg=`echo "x$opt" |sed 's/^[^=]*=//'`
   case "$opt" in
   --help|-h) show_help=yes
   ;;