# Regexp#fixed\_encoding?

**URL:** <https://www.ruby-forum.com/t/regexp-fixed-encoding/121252>\
**Category:** Development\
**Created:** [November 26, 2007, 3:40am UTC](https://www.ruby-forum.com/t/regexp-fixed-encoding/121252 "2007-11-26T03:40:20Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [November 26, 2007, 3:40am UTC](https://www.ruby-forum.com/t/regexp-fixed-encoding/121252/1 "2007-11-26T03:40:20Z")

</div>

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e$B$=$N\<oN`$rH=JL$9$k$?$a$K!"e(BRegexp#fixed\_encoding? e$B$r:n$k$N$Oe(B  
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% ./ruby -e ‘p /a/.fixed\_encoding?’  
false  
% ./ruby -e ‘p /a/e.fixed\_encoding?’  
true

1.8 e$B$G$O$3$l$K;w$?\>pJs$re(B Regexp#kcode e$B$GF@$i$l$^$7$?$,!“e(B1.9  
e$B$K$Oe(B kcode e$B$,$”$j$^$;$s!#e(B

% ruby-1.8 -e ‘p /a/.kcode’  
nil  
% ruby-1.8 -e ‘p /a/e.kcode’  
“euc”

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# Index: re.c

— re.c (revision 14018)  
+++ re.c (working copy)  
@@ -2198,6 +2198,7 @@ Init\_Regexp(void)  
rb\_define\_method(rb\_cRegexp, “casefold?”, rb\_reg\_casefold\_p, 0);  
rb\_define\_method(rb\_cRegexp, “options”, rb\_reg\_options\_m, 0);  
rb\_define\_method(rb\_cRegexp, “encoding”, rb\_obj\_encoding, 0); /\* in  
encoding.c \*/

- rb\_define\_method(rb\_cRegexp, “fixed\_encoding?”,  
rb\_reg\_fixed\_encoding\_p, 0);

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [November 26, 2007, 9:26am UTC](https://www.ruby-forum.com/t/regexp-fixed-encoding/121252/2 "2007-11-26T09:26:50Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:32361] Regexp#fixed\_encoding?”  
on Mon, 26 Nov 2007 11:39:31 +0900, Tanaka A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:  
|  
|e$B@55,I=8=$K$O!"G$0U$Ne(B (ASCII e$B8\_49$Je(B) e$B%(%s%3!\<%G%#%s%0$NJ8;zNse(B  
|e$B$H%^%C%A$5$;$i$l$k$+!"FCDj$N%(%s%3!\<%G%#%s%0$NJ8;zNs$K$7$+%^%Ce(B  
|e$B%A$5$;$i$l$J$$$+$H$$$&\<oN`$,$"$j$^$9!#e(B | |e$B$=$N<oN`$rH=JL$9$k$?$a$K!"e(BRegexp#fixed\_encoding? e$B$r:n$k$N$Oe(B  
|e$B$I$&$G$7$g$&$+!#e(B

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