# Binmode and ASCII-8BIT

**URL:** <https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474>\
**Category:** Development\
**Created:** [January 9, 2008, 1:40pm UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474 "2008-01-09T13:40:57Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 9, 2008, 1:40pm UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/1 "2008-01-09T13:40:57Z")

</div>

e$B@\>;3OB9-$G$9!#e(B

[http://dontstopmusic.no-ip.org/diary/20080106.html#p02](http://dontstopmusic.no-ip.org/diary/20080106.html#p02)  
e$B$r8+$F$A$g$C$HD4$Y$F$\_$?$N$G$9$,!"e(B

- binmode e$B$Ge(B external\_encoding e$B$,e(B ASCII-8BIT e$B$K$J$ke(B
- external\_encoding e$B$,e(B ASCII-8BIT e$B$@$He(B ASCII-8BIT  
e$B0J30$N%(%s%3!\<%G%#%s%0$Ne(B  
ascii\_only e$B$G$O$J$$J8;zNs$,=PNO$G$-$J$$e(B
- nil e$B$He(B ASCII-8BIT  
e$B$,F1$807$$$N%a%=%C%I$H0c$&07$$$N%a%=%C%I$,$"$ke(B  
e$B$H$$$&$N$O;EMM$G$7$g$&$+e(B?

e$B2~9T$NJQ49$@$1;\_$a$F$[$7$$\>l9g$Oe(B .binmode.set\_encoding(nil)  
e$B$Ke(B  
e$B$J$k$N$G$7$g$&$+e(B?

% ruby-trunk -v  
ruby 1.9.0 (2008-01-09 revision 0) [i686-linux]  
% ruby-trunk -e ‘Encoding.find(nil)’  
-e:1:in `find': can't convert nil into String (TypeError) from -e:1:in `’  
% ruby-trunk -e ‘p “”.encode(nil).encoding’  
#Encoding:ASCII-8BIT  
% ruby-trunk -e ‘p “”.encode(Encoding::ASCII\_8BIT).encoding’  
#Encoding:ASCII-8BIT  
% ruby-trunk -e ‘p  
STDERR.set\_encoding(Encoding::ASCII\_8BIT).external\_encoding’  
#Encoding:ASCII-8BIT  
% ruby-trunk -e ‘p STDERR.set\_encoding(nil).external\_encoding’  
nil  
% ruby-trunk -e ‘p STDERR.binmode.external\_encoding’  
#Encoding:ASCII-8BIT  
%

% ruby-trunk -E euc-jp -e ‘p “\xFF”.encoding’  
#Encoding:EUC-JP  
% ruby-trunk -E euc-jp -e ‘p  
“\xFF”.force\_encoding(Encoding::ASCII\_8BIT).encoding’  
#Encoding:ASCII-8BIT  
% ruby-trunk -E euc-jp -e ‘p “\xFF”.force\_encoding(nil).encoding’  
#Encoding:ASCII-8BIT  
%

---

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 9, 2008, 6:27pm UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/2 "2008-01-09T18:27:24Z")

</div>

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

In message “Re: [ruby-dev:32996] binmode and ASCII-8BIT”  
on Wed, 9 Jan 2008 21:39:00 +0900, Kazuhiro NISHIYAMA  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|[http://dontstopmusic.no-ip.org/diary/20080106.html#p02](http://dontstopmusic.no-ip.org/diary/20080106.html#p02)  
|e$B$r8+$F$A$g$C$HD4$Y$F$\_$?$N$G$9$,!“e(B  
| \* binmode e$B$Ge(B external\_encoding e$B$,e(B ASCII-8BIT e$B$K$J$ke(B  
| \* external\_encoding e$B$,e(B ASCII-8BIT e$B$@$He(B ASCII-8BIT e$B0J30$N%(%s%3!\<%G%#%s%0$Ne(B  
| ascii\_only e$B$G$O$J$$J8;zNs$,=PNO$G$-$J$$e(B  
| \* nil e$B$He(B ASCII-8BIT e$B$,F1$807$$$N%a%=%C%I$H0c$&07$$$N%a%=%C%I$,$”$ke(B  
|e$B$H$$$&$N$O;EMM$G$7$g$&$+e(B?

e$B=gHV$K!#e(B

- binmode e$B$Ge(B external\_encoding e$B$,e(B ASCII-8BIT e$B$K$J$ke(B

e$B;EMM!"$G$7$?!#e(BMartine$B$5$s$+$i;XE&$r\<u$1$F!“e(Bencodinge$B$K$O\<j$r2Ce(B  
e$B$($J$$$h$&$K$9$k$3$H$K$7$^$7$?!#$,!”$^$@\<BAu$KH?1G$5$l$F$^$;e(B  
e$B$s!#e(B

- external\_encoding e$B$,e(B ASCII-8BIT e$B$@$He(B ASCII-8BIT  
e$B0J30$N%(%s%3!\<%G%#%s%0$Ne(B  
ascii\_only e$B$G$O$J$$J8;zNs$,=PNO$G$-$J$$e(B

e$BL@\<(E\*$K;XDj$7$?\>l9g$K$OJQ49$,9T$o$l$^$9$+$i!“=PNO$N\>l9g$K$Oe(B  
e$B%(%s%3!\<%G%#%s%0$r;XDj$7$J$$$3$H$r$\*A&$a$7$^$9!#$?$@$7!”$3$Ne(B  
e$B%(%s%H%j$N\>l9g$K$Oe(Bbinmodee$B$,\>!\<j$K;XDj$7$F$$$k$o$1$G$9$,!#$3$le(B  
e$B$O%P%0G’Dj$G$9!#e(B

- nil e$B$He(B ASCII-8BIT  
e$B$,F1$807$$$N%a%=%C%I$H0c$&07$$$N%a%=%C%I$,$"$ke(B

Stringe$B$_$h$Se(BEncodinge$B$G$Oe(Bnile$B$O%(%s%3!\<%G%#%s%0$H$7$F;XDj$G$-e(B  
e$B$^$;$s!#e(BIOe$B$K$_$$$F$O!V%(%s%3!\<%G%#%s%0$r;XDj$7$J$$!W$H$$$&0Ue(B  
e$BL#$K$J$j$^$9!#$=$l0J30$G!V0c$&07$$!W$,$"$l$P65$($F$/$@$5$$!#e(B

|e$B2~9T$NJQ49$@$1;\_$a$F$[$7$$\>l9g$Oe(B .binmode.set\_encoding(nil) e$B$Ke(B  
|e$B$J$k$N$G$7$g$&$+e(B?

binmodee$B$@$1$Ge(BOKe$B$K$J$kM=Dj$G$9!#e(B

```
                            e$B$^$D$b$He(B e$B$f$-$R$me(B /:|)

```

---

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 10, 2008, 2:17am UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/3 "2008-01-10T02:17:47Z")

</div>

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

In message “Re: [ruby-dev:33000] Re: binmode and ASCII-8BIT”  
on Thu, 10 Jan 2008 08:36:47 +0900, sheepman  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|IO.pipe e$B$NBhe(B2e$B0z?t$Ke(B nil e$B$r;XDj$7$?;~$KFbIt%(%s%3!\<%G%#%s%0$,e(B  
|e$B0J2\<$N$h$&$K$J$k$N$O%P%0$G$7$g$&$+!#e(B  
|  
|$ cat pipe.rb  
|p IO.pipe(Encoding::EUC\_JP)[0].internal\_encoding  
|p IO.pipe(Encoding::EUC\_JP, nil)[0].internal\_encoding  
|  
|$ ruby-1.9 -Ks -v pipe.rb  
|ruby 1.9.0 (2008-01-07 revision 0) [i686-linux]  
|nil  
|#Encoding:Windows-31J

e$B%P%0$G$9$M!#$"$j$,$H$&$4$6$$$^$9!#e(B

---

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 10, 2008, 12:37am UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/4 "2008-01-10T00:37:48Z")

</div>

e$B$3$s$K$A$Oe(B sheepman e$B$G$9!#e(B

On Thu, 10 Jan 2008 02:26:30 +0900  
Yukihiro M. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> - nil e$B$He(B ASCII-8BIT e$B$,F1$807$$$N%a%=%C%I$H0c$&07$$$N%a%=%C%I$,$"$ke(B
> 
> Stringe$B$_$h$Se(BEncodinge$B$G$Oe(Bnile$B$O%(%s%3!\<%G%#%s%0$H$7$F;XDj$G$-e(B  
> e$B$^$;$s!#e(BIOe$B$K$_$$$F$O!V%(%s%3!\<%G%#%s%0$r;XDj$7$J$$!W$H$$$&0Ue(B  
> e$BL#$K$J$j$^$9!#$=$l0J30$G!V0c$&07$$!W$,$"$l$P65$($F$/$@$5$$!#e(B

IO.pipe e$B$NBhe(B2e$B0z?t$Ke(B nil  
e$B$r;XDj$7$?;~$KFbIt%(%s%3!\<%G%#%s%0$,e(B  
e$B0J2\<$N$h$&$K$J$k$N$O%P%0$G$7$g$&$+!#e(B

$ cat pipe.rb  
p IO.pipe(Encoding::EUC\_JP)[0].internal\_encoding  
p IO.pipe(Encoding::EUC\_JP, nil)[0].internal\_encoding

$ ruby-1.9 -Ks -v pipe.rb  
ruby 1.9.0 (2008-01-07 revision 0) [i686-linux]  
nil  
#Encoding:Windows-31J

---

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 10, 2008, 3:41am UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/5 "2008-01-10T03:41:30Z")

</div>

e$B$J$+$@$G$9!#e(B

At Thu, 10 Jan 2008 02:26:30 +0900,  
Yukihiro M. wrote in [ruby-dev:32998]:

> - nil e$B$He(B ASCII-8BIT e$B$,F1$807$$$N%a%=%C%I$H0c$&07$$$N%a%=%C%I$,$"$ke(B
> 
> Stringe$B$_$h$Se(BEncodinge$B$G$Oe(Bnile$B$O%(%s%3!\<%G%#%s%0$H$7$F;XDj$G$-e(B  
> e$B$^$;$s!#e(BIOe$B$K$_$$$F$O!V%(%s%3!\<%G%#%s%0$r;XDj$7$J$$!W$H$$$&0Ue(B  
> e$BL#$K$J$j$^$9!#$=$l0J30$G!V0c$&07$$!W$,$"$l$P65$($F$/$@$5$$!#e(B

Stringe$B$G$H$$$&$N$Oe(Bforce\_encodinge$B$G$7$g$&$+!#e(B

$ ./ruby -e ‘p “\u3000”.force\_encoding(nil).encoding’  
#Encoding:ASCII-8BIT

e$B$H$$$&$h$&$K!“8=\>u$G$O%(%s%3!\<%G%#%s%0;XDj$H$7$Fe(BEncodinge$B!”%(%s%3!\<e(B  
e$B%G%#%s%0L\>$^$?$Oe(Bnile$B$r\<u$1IU$1$^$9$,!"D\>$9$Y$-$G$7$g$&$+!#e(B

Encoding.finde$B$K$D$$$F$O!"%(%s%3!\<%G%#%s%0L\>$+$ie(BEncodinge$B%_%V%8%'e(B  
e$B%/%H$rJV$9%a%=%C%I$J$N$G!"e(BStringe$B0J30e(BEncodinge$B$be(Bnile$B$b\<u$1IU$1$^$;e(B  
e$B$s!#$3$l$O\>e5-$N!V%(%s%3!\<%G%#%s%0;XDj!W$H$OJLJ_$G$"$k$H9M$($F$$e(B  
e$B$^$9!#e(Bforce\_encodinge$B$J$I$bK\Mhe(BEncodinge$B%_%V%8%’%/%H$r\<u$1\<h$k$Y$-e(B  
e$B$@$1$l$I!“4JJX$5$N$?$a$K%(%s%3!\<%G%#%s%0L\>$G$”$l$P\<+F0E_$Ke(B  
Encoding.finde$B$7$F$$$k$@$1$G!#e(B

---

<div class="post-metadata">

**Author:** ![Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/k/77aa72/32.png) [@Kazuhiro\_NISHIYAMA](https://www.ruby-forum.com/u/Kazuhiro_NISHIYAMA)\
**Post date:** [January 10, 2008, 3:56am UTC](https://www.ruby-forum.com/t/binmode-and-ascii-8bit/125474/6 "2008-01-10T03:56:06Z")

</div>

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

In message “Re: [ruby-dev:33002] Re: binmode and ASCII-8BIT”  
on Thu, 10 Jan 2008 11:40:43 +0900, Nobuyoshi N.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

|Stringe$B$G$H$$$&$N$Oe(Bforce\_encodinge$B$G$7$g$&$+!#e(B  
|  
| $ ./ruby -e ‘p “\u3000”.force\_encoding(nil).encoding’  
| #Encoding:ASCII-8BIT  
|  
|e$B$H$$$&$h$&$K!“8=\>u$G$O%(%s%3!\<%G%#%s%0;XDj$H$7$Fe(BEncodinge$B!”%(%s%3!\<e(B  
|e$B%G%#%s%0L\>$^$?$Oe(Bnile$B$r\<u$1IU$1$^$9$,!"D\>$9$Y$-$G$7$g$&$+!#e(B

nile$B$Oe(BASCII-8BITe$B$r;XDj$7$?$3$H$K$J$k$h$&$G$9$M!#5v$9$3$H$N%ae(B  
e$B%j%C%H$,;W$$$D$+$J$$$N$G$9$,!"$b$7%a%j%C%H$,$J$1$l$PD\>$9$Y$-e(B  
e$B$G$7$g$&$M!#e(B