Re: printf \xNNN

[Jim Meyering]

Padraig Brady <address@hidden> wrote:
> Why [ :-) ] does printf take up to 3 hex digits?
> What's wrong with 2 (lastest bash just does 2).
>
> $ /usr/bin/printf "\xf73"
> s
> $ printf "\xf73"
> ÷3
>
> printf from sh-utils just ignored the first hex digit?

Thank you for the report!
That looks like a bug.
It is at least 10 years old, since that code was there for my
initial cvs import on Nov 1, 1992.

Index: printf.c
===================================================================
RCS file: /fetish/cu/src/printf.c,v
retrieving revision 1.70
diff -u -p -u -p -r1.70 printf.c
--- printf.c    13 Sep 2002 09:50:23 -0000      1.70
+++ printf.c    6 Nov 2002 08:52:59 -0000
@@ -240,11 +240,11 @@ print_esc (const char *escstart)
   int esc_value = 0;           /* Value of \nnn escape. */
   int esc_length;              /* Length of \nnn escape. */
 
-  /* \0ooo and \xhhh escapes have maximum length of 3 chars. */
   if (*p == 'x')
     {
+      /* A hexadecimal \xhh escape sequence must have 1 or 2 hex. digits.  */
       for (esc_length = 0, ++p;
-          esc_length < 3 && ISXDIGIT (*p);
+          esc_length < 2 && ISXDIGIT (*p);
           ++esc_length, ++p)
        esc_value = esc_value * 16 + hextobin (*p);
       if (esc_length == 0)
@@ -253,6 +253,8 @@ print_esc (const char *escstart)
     }
   else if (*p == '0')
     {
+      /* An octal \0ooo escape sequence has 0 to 3 octal digits
+        after the leading \0.  */
       for (esc_length = 0, ++p;
           esc_length < 3 && isodigit (*p);
           ++esc_length, ++p)