# File.read produces \\0 as the first byte

**URL:** <https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138>\
**Category:** Development\
**Created:** [September 1, 2006, 12:07am UTC](https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138 "2006-09-01T00:07:21Z")\
**Posts on this page:** 4\
**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:** [September 1, 2006, 12:07am UTC](https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138/1 "2006-09-01T00:07:21Z")

</div>

File.read e$B$Ge(B /proc/self/status e$B$rFI$s$@$H$-$K!":G=i$N%P%$%He(B  
e$B$,e(B \0 e$B$K$J$j$^$9!#e(B

% ./ruby -ve ‘p File.read("/proc/self/status")’  
ruby 1.9.0 (2006-08-31) [i686-linux]  
“\000ame:\truby\nState:\tR  
(running)\nSleepAVG:\t88%\nTgid:\t20549\nPid:\t20549\nPPid:\t10271\nTracerPid:\t0\nUid:\t1000\t1000\t1000\t1000\nGid:\t1000\t1000\t1000\t1000\nFDSize:\t32\nGroups:\t20  
24 25 29 44 46 1000 \nVmPeak:\t 3220 kB\nVmSize:\t 3220  
kB\nVmLck:\t 0 kB\nVmHWM:\t 1488 kB\nVmRSS:\t 1488  
kB\nVmData:\t 752 kB\nVmStk:\t 84 kB\nVmExe:\t 848  
kB\nVmLib:\t 1464 kB\nVmPTE:\t 12  
kB\nThreads:\t1\nSigQ:\t0/4294967295\nSigPnd:\t0000000000000000\nShdPnd:\t0000000000000000\nSigBlk:\t0000000000000000\nSigIgn:\t0000000000000000\nSigCgt:\t0000000000003a07\nCapInh:\t0000000000000000\nCapPrm:\t0000000000000000\nCapEff:\t0000000000000000\n”

gets e$B$GFI$`$H$=$&$O$J$j$^$;$s!#e(B

% ./ruby -e ‘open("/proc/self/status") {|f| p f.gets }’  
“Name:\truby\n”

---

<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:** [September 1, 2006, 2:19am UTC](https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138/2 "2006-09-01T02:19:30Z")

</div>

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

At Fri, 1 Sep 2006 07:06:58 +0900,  
Tanaka A. wrote in [ruby-dev:29368]:

> File.read e$B$Ge(B /proc/self/status e$B$rFI$s$@$H$-$K!":G=i$N%P%$%He(B  
> e$B$,e(B \0 e$B$K$J$j$^$9!#e(B

embede$B$+$ie(Bnoembede$B$Ke(Bresizee$B$9$k$H$-$K4{B8$NFbMF$r%3%T!\<$7$F$$$J$$e(B  
e$B$h$&$G$9!#e(B

e$B$D$$$G$Ke(B64bite$B4D6-$@$He(BRSTRING\_EMBED\_LEN\_MASKe$B$,B-$j$J$/$J$j$=$&$Je(B  
e$B7o$b!#e(B

# Index: ruby.h

RCS file: /cvs/ruby/src/ruby/ruby.h,v  
retrieving revision 1.148  
diff -p -u -2 -r1.148 ruby.h  
— ruby.h 31 Aug 2006 10:47:43 -0000 1.148  
+++ ruby.h 1 Sep 2006 00:11:33 -0000  
@@ -363,5 +363,5 @@ struct RFloat {  
#define ELTS\_SHARED FL\_USER2

# -#define RSTRING\_EMBED\_LEN\_MAX ((sizeof(VALUE)_3)/sizeof(char)-1) +#define RSTRING\_EMBED\_LEN\_MAX (SIZEOF\_VALUE_3-1) struct RString { struct RBasic basic; @@ -381,4 +381,8 @@ struct RString { #define RSTRING\_EMBED\_LEN\_MASK (FL\_USER2|FL\_USER3|FL\_USER4|FL\_USER5) #define RSTRING\_EMBED\_LEN\_SHIFT (FL\_USHIFT+2) +#if RSTRING\_EMBED\_LEN\_MAX \> (RSTRING\_EMBED\_LEN\_MASK \>\> RSTRING\_EMBED\_LEN\_SHIFT) +#undef RSTRING\_EMBED\_LEN\_MAX +#define RSTRING\_EMBED\_LEN\_MAX (RSTRING\_EMBED\_LEN\_MASK \>\> RSTRING\_EMBED\_LEN\_SHIFT) +#endif #define RSTRING\_LEN(str) (!(RBASIC(str)-\>flags & RSTRING\_NOEMBED) ? Index: string.c

RCS file: /cvs/ruby/src/ruby/string.c,v  
retrieving revision 1.258  
diff -p -u -2 -r1.258 string.c  
— string.c 31 Aug 2006 10:47:43 -0000 1.258  
+++ string.c 1 Sep 2006 00:12:08 -0000  
@@ -683,4 +683,5 @@ rb\_str\_resize(VALUE str, long len)  
if (len != RSTRING\_LEN(str)) {  
if (STR\_EMBED\_P(str)) {

- 

```
  char *ptr;
  if (len <= RSTRING_EMBED_LEN_MAX) {
  STR_SET_EMBED_LEN(str, len);

```

@@ -688,5 +689,7 @@ rb\_str\_resize(VALUE str, long len)  
return str;  
}

- 

```
  RSTRING(str)->as.heap.ptr = ALLOC_N(char,len+1);

```

- 

```
  ptr = ALLOC_N(char, len+1);

```

- 

```
  MEMCPY(ptr, RSTRING(str)->ary, char, RSTRING_LEN(str));

```

- 

```
  RSTRING(str)->as.heap.ptr = ptr;
  STR_SET_NOEMBED(str);

```

}  
@@ -4166,5 +4169,5 @@ rb\_str\_ord(VALUE s)  
if (RSTRING\_LEN(s) != 1) {  
rb\_raise(rb\_eTypeError,

- 

```
   "expacted a characer, but string of size %d given",

```

- 

```
   "expacted a characer, but string of size %ld given",
   RSTRING_LEN(s));

```

}

---

<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:** [September 1, 2006, 3:01am UTC](https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138/3 "2006-09-01T03:01:33Z")

</div>

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

In message “Re: [ruby-dev:29369] Re: File.read produces \0 as the first  
byte.”  
on Fri, 1 Sep 2006 09:17:28 +0900, removed\_email\_address@domain.invalid writes:

|At Fri, 1 Sep 2006 07:06:58 +0900,  
|Tanaka A. wrote in [ruby-dev:29368]:  
|\> File.read e$B$Ge(B /proc/self/status e$B$rFI$s$@$H$-$K!":G=i$N%P%$%He(B  
|\> e$B$,e(B \0 e$B$K$J$j$^$9!#e(B  
|  
|embede$B$+$ie(Bnoembede$B$Ke(Bresizee$B$9$k$H$-$K4{B8$NFbMF$r%3%T!\<$7$F$$$J$$e(B  
|e$B$h$&$G$9!#e(B  
|  
|e$B$D$$$G$Ke(B64bite$B4D6-$@$He(BRSTRING\_EMBED\_LEN\_MASKe$B$,B-$j$J$/$J$j$=$&$Je(B  
|e$B7o$b!#e(B

e$B%3%\_%C%H$7$F$/$@$5$$!#e(B64bite$B4D6-$K$D$$$F$O9M$($F$^$;$s$G$7$?!#e(B  
e$B=$9T$,B-$j$J$$!#e(B

---

<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:** [September 1, 2006, 3:00pm UTC](https://www.ruby-forum.com/t/file-read-produces-0-as-the-first-byte/67138/4 "2006-09-01T15:00:18Z")

</div>

In article [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid),  
removed\_email\_address@domain.invalid writes:

> e$B$D$$$G$Ke(B64bite$B4D6-$@$He(BRSTRING\_EMBED\_LEN\_MASKe$B$,B-$j$J$/$J$j$=$&$Je(B  
> e$B7o$b!#e(B

e$B$b$&e(B 1bit e$B;H$C$Fe(B 23byte  
e$B$^$GI=8=$G$-$k$h$&$K$7$?$[$&$,$$$$$se(B  
e$B$8$c$J$$$+$H;W$$$^$9!#e(B