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Re: strncpy and 'n'

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jgk@panix.com (Joe keane) writes:
> In article <lnboouef7m.fsf@nuthaus.mib.org>,
> Keith Thompson  <kst-u@mib.org> wrote:
>>If it had been defined something like this:
>>
>>    char *better_strncpy(char *dest, const char *src, size_t n) {
>>        dest[0] = '\0';
>>        return strncat(dest, src, n);
>>    }
>>
>>then it would be reasonable to call it a "safer" version of strcpy.
>
> Well there you go.  You pretty much solved your complaint.  It you are
> catenating several strings, it's almost more natural to zero out at the
> beginning, then use 'strcat' from there.

Not really.  My complaint is that strncpy() is in the standard library
with the name "strncpy", and that too many programmers use it
incorrectly.

> You can understand why you might want to zero out the whole array at the
> start; from there 'strcat' is fine.

Note that multiple strcat() calls can be quite inefficient, since
each one has to scan the destination to find the terminating '\0'
before it appends the new data.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

strncpy and 'n' nroberts <roberts.noah@gmail.com> - 2012-02-16 09:05 -0800
  Re: strncpy and 'n' Anders Wegge Keller <wegge@wegge.dk> - 2012-02-16 18:57 +0100
    Re: strncpy and 'n' "A. K." <akk@nospam.org> - 2012-02-16 19:27 +0100
      Re: strncpy and 'n' Anders Wegge Keller <wegge@wegge.dk> - 2012-02-16 19:34 +0100
        Re: strncpy and 'n' "A. K." <akk@nospam.org> - 2012-02-16 20:58 +0100
  Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-16 10:01 -0800
    Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-16 11:10 -0800
      Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-16 14:20 -0800
        Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-17 04:19 -0800
          Re: strncpy and 'n' James Kuyper <jameskuyper@verizon.net> - 2012-02-17 10:04 -0500
            Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-17 10:27 -0800
            Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-17 11:22 -0800
              Re: strncpy and 'n' James Kuyper <jameskuyper@verizon.net> - 2012-02-17 14:40 -0500
                Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-18 02:17 -0800
    Re: strncpy and 'n' jgk@panix.com (Joe keane) - 2012-02-19 20:04 +0000
      Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-19 12:33 -0800
        Re: strncpy and 'n' jgk@panix.com (Joe keane) - 2012-02-20 21:25 +0000
          Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-20 14:46 -0800
            Re: strncpy and 'n' Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-23 23:13 +0000
              Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-23 16:20 -0800
              Re: strncpy and 'n' Philip Lantz <prl@canterey.us> - 2012-02-25 00:26 -0800
              Re: strncpy and 'n' pacman@kosh.dhis.org (Alan Curry) - 2012-02-26 01:34 +0000
                Re: strncpy and 'n' Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-02-28 22:46 +0000
                Re: strncpy and 'n' jgk@panix.com (Joe keane) - 2012-03-01 00:03 +0000
                Re: strncpy and 'n' Jorgen Grahn <grahn+nntp@snipabacken.se> - 2012-03-01 12:03 +0000
          Re: strncpy and 'n' James Kuyper <jameskuyper@verizon.net> - 2012-02-20 17:51 -0500
        Re: strncpy and 'n' Shao Miller <sha0.miller@gmail.com> - 2012-02-20 18:14 -0500
          Re: strncpy and 'n' pete <pfiland@mindspring.com> - 2012-02-20 23:16 -0500
            Re: strncpy and 'n' Shao Miller <sha0.miller@gmail.com> - 2012-02-25 01:51 -0500
              Re: strncpy and 'n' pete <pfiland@mindspring.com> - 2012-02-25 10:34 -0500
        Re: strncpy and 'n' Rich Webb <bbew.ar@mapson.nozirev.ten> - 2012-02-20 19:09 -0500
          Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-20 16:46 -0800
            Re: strncpy and 'n' Rich Webb <bbew.ar@mapson.nozirev.ten> - 2012-02-20 20:48 -0500
          Re: strncpy and 'n' Shao Miller <sha0.miller@gmail.com> - 2012-02-20 19:46 -0500
        Re: strncpy and 'n' jgk@panix.com (Joe keane) - 2012-02-21 21:46 +0000
          Re: strncpy and 'n' James Kuyper <jameskuyper@verizon.net> - 2012-02-21 17:15 -0500
          Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-21 14:29 -0800
            Re: strncpy and 'n' Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-02-22 01:15 -0800
            Re: strncpy and 'n' jgk@panix.com (Joe keane) - 2012-02-23 00:02 +0000
              Re: strncpy and 'n' Keith Thompson <kst-u@mib.org> - 2012-02-22 17:02 -0800
  Re: strncpy and 'n' Markus Schaub <usenet@markus-schaub.de> - 2012-02-16 18:53 +0000
  Re: strncpy and 'n' lawrence.jones@siemens.com - 2012-02-16 13:25 -0500
  Re: strncpy and 'n' blp@cs.stanford.edu (Ben Pfaff) - 2012-02-16 11:18 -0800
  Re: strncpy and 'n' Stephen Sprunk <stephen@sprunk.org> - 2012-02-16 13:29 -0600
    Re: strncpy and 'n' Ike Naar <ike@iceland.freeshell.org> - 2012-02-16 22:45 +0000
  Re: strncpy and 'n' ImpalerCore <jadill33@gmail.com> - 2012-02-16 11:32 -0800
  Re: strncpy and 'n' Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-02-17 00:50 -0800

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