How i convert from Wt::WString to std::string

Hello,

Excuse me for my rookie question. I'm new in the C and Wt world :)

I have problems with the Wt::WString and std::string c .

I would like to make a normal C string from a composite WString. Unfortunately, it fails with the following error:

error: cannot convert 'Wt::WString' to 'std::__cxx11::string* {aka std::__cxx11::basic_string<char>*}' in assignment
  dest->valueText() + " " + user->text() + " " + passwort->text() ;
                                                                ^
clientTab.hpp:64:51: error: no matching function for call to 'Wt::WText::setText(std::__cxx11::string*&)'
     target_name_box->setText( target_name_command );

can you help me, please?

   Wt::WSelectionBox* dest;
   Wt::WText* target_name_box;
   std::string* target_name_command;

   void update_text_box() {

     // output update helper
     target_name_command =
        "iqn." + date->text() + ".de.xxx." + ip->text() + ":" +
         hardware->text() + ":" + button_label + "." + mac->text() + ".img" +
         " " + volume->valueText() + " " + image->valueText() + " " +
         dest->valueText() + " " + user->text() + " " + passwort->text() ;

     target_name_box->setText( target_name_command );

         pbCheck->setCommand(  key_to_command["controller"] + target_name_command );

Replies (4)

RE: How i convert from Wt::WString to std::string - Added by Wim Dumon about 8 years ago

Hey Chris,

Wt needs some hint regarding the character encoding of the strings you want to convert WString to a std::wstring. Given UTF-8's popularity nowadays, this is usually as simple as calling fromUTF8() and toUTF8() on WStrings:

"iqn." + date->text().toUTF8() + ...

On the other hand, looking at your code, I would suggest you skip the conversion between WString and std::string alltogether in your concatenation step:

   Wt::WSelectionBox* dest;
   Wt::WText* target_name_box;
   // note: std::string* or WString* would not work here, this has to be a value variable
   WString target_name_command;

   void update_text_box() {

     // output update helper
     target_name_command =
        "iqn." + date->text() + ".de.xxx." + ip->text() + ":" +
         hardware->text() + ":" + button_label + "." + mac->text() + ".img" +
         " " + volume->valueText() + " " + image->valueText() + " " +
         dest->valueText() + " " + user->text() + " " + passwort->text() ;

     target_name_box->setText( target_name_command );

         pbCheck->setCommand(  key_to_command["controller"] + target_name_command );

Then convert your target command to an std::string when you need to, in the proper encoding (for UTF-8, this would be target_name_command.toUTF8()).

Wim.

RE: How i convert from Wt::WString to std::string - Added by Chris immer about 8 years ago

hi Wim,

thank you for your quick reply. It works.

the reason, why i'm try to converting it. I give the string to a bash script and always i get a $'\r' carriage return in the end of my string. I don't want that. Do you have an idea why?

RE: How i convert from Wt::WString to std::string - Added by Wim Dumon about 8 years ago

Chris,

Sorry, I can't see a reason why the \r would be added. This should work:

std::string command_string = target_name_command.toUTF8();

system(command_string.c_str());

Carefully sanitize your inputs, or you have just created an easily exploitable attack vector :)

Wim.

RE: How i convert from Wt::WString to std::string - Added by Chris immer about 8 years ago

thanks for your hint,

you mean my wt inputs are not so good?

is that right? i am grateful about every tip or link.

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