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Re: double strtod( const char *nPtr, char **endPrt);

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Malcolm McLean wrote:
> On Friday, November 13, 2015 at 1:09:51 AM UTC, Ian Collins wrote:
>> Malcolm McLean wrote:
>>
>>> (C++ can actually crash if you try to call an analagous function
>>> on the c_str() return from a const std::string. That happened to
>>> me today. I had to copy the string to a temporary. This is despite
>>> never writing to the pointer).
>>
>> Which one?
>>
> The code was
>
> JSONparser::JSONParser(const std::string &json);
>
> std::string const &aClass::getData() { return mData;};
>
> void myobject::foo(const aClass &aParam)
> {
>     // data string has JSON attached to it
>     JSONParser jparser(strchr(aParam().getData().c_str(), '{'));

Well strchr() is one of the functions where C++ provides the correct 
overload, so your problem had nothing to do with const.

This type of crash usually occurs when the original string object goes 
out of scope and the data pointer is invalid.

-- 
Ian Collins

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double strtod( const char *nPtr, char **endPrt); G G <gdotone@gmail.com> - 2015-11-11 22:55 -0800
  Re: double strtod( const char *nPtr, char **endPrt); Richard Heathfield <rjh@cpax.org.uk> - 2015-11-12 07:24 +0000
    Re: double strtod( const char *nPtr, char **endPrt); G G <gdotone@gmail.com> - 2015-11-11 23:42 -0800
  Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 08:31 -0800
    Re: double strtod( const char *nPtr, char **endPrt); supercat@casperkitty.com - 2015-11-12 08:52 -0800
    Re: double strtod( const char *nPtr, char **endPrt); G G <gdotone@gmail.com> - 2015-11-12 09:43 -0800
      Re: double strtod( const char *nPtr, char **endPrt); Richard Heathfield <rjh@cpax.org.uk> - 2015-11-12 17:59 +0000
      Re: double strtod( const char *nPtr, char **endPrt); Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-12 13:10 -0500
      Re: double strtod( const char *nPtr, char **endPrt); James Kuyper <jameskuyper@verizon.net> - 2015-11-12 13:19 -0500
      Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 11:32 -0800
        Re: double strtod( const char *nPtr, char **endPrt); supercat@casperkitty.com - 2015-11-12 12:17 -0800
          Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 12:48 -0800
            Re: double strtod( const char *nPtr, char **endPrt); supercat@casperkitty.com - 2015-11-12 13:39 -0800
              Re: double strtod( const char *nPtr, char **endPrt); glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-12 23:24 +0000
              Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 17:14 -0800
                Re: double strtod( const char *nPtr, char **endPrt); supercat@casperkitty.com - 2015-11-12 17:42 -0800
                Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 18:20 -0800
            Re: double strtod( const char *nPtr, char **endPrt); glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-12 23:15 +0000
              Re: double strtod( const char *nPtr, char **endPrt); Eric Sosman <esosman@comcast-dot-net.invalid> - 2015-11-12 18:30 -0500
                Re: double strtod( const char *nPtr, char **endPrt); supercat@casperkitty.com - 2015-11-12 16:47 -0800
                Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 18:07 -0800
                Re: double strtod( const char *nPtr, char **endPrt); glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-13 02:41 +0000
                Re: double strtod( const char *nPtr, char **endPrt); glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-11-13 02:53 +0000
        Re: double strtod( const char *nPtr, char **endPrt); G G <gdotone@gmail.com> - 2015-11-12 12:17 -0800
  Re: double strtod( const char *nPtr, char **endPrt); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-12 12:34 -0800
    Re: double strtod( const char *nPtr, char **endPrt); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-12 23:54 +0000
      Re: double strtod( const char *nPtr, char **endPrt); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-12 16:23 -0800
        Re: double strtod( const char *nPtr, char **endPrt); Ian Collins <ian-news@hotmail.com> - 2015-11-13 14:09 +1300
          Re: double strtod( const char *nPtr, char **endPrt); Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-11-12 17:31 -0800
            Re: double strtod( const char *nPtr, char **endPrt); Ian Collins <ian-news@hotmail.com> - 2015-11-13 14:46 +1300
        Re: double strtod( const char *nPtr, char **endPrt); Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-11-13 02:07 +0000
        Re: double strtod( const char *nPtr, char **endPrt); David Brown <david.brown@hesbynett.no> - 2015-11-13 08:48 +0100
    Re: double strtod( const char *nPtr, char **endPrt); Keith Thompson <kst-u@mib.org> - 2015-11-12 16:57 -0800

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