wxWidgets Hello World example not compiling

Question

I'm trying to learn the wxWidgets framework as I've been assigned to work on a project which already uses the library.

I am using it on a Raspberry Pi, having installed it using sudo apt-get install libwxgtk2.8-dev libwxgtk2.8-dbg.

I found this tutorial on the wxWidgets website and pasted it into a file called hello.cpp on my Pi.

Then I ran g++ hello.cpp -o hellowx-config --cxxflags --libs` and I got the following enormous error message:

gcc hello.cpp -o hello `wx-config --cxxflags --libs`
hello.cpp:20:27: error: ISO C++ forbids declaration of ‘wxDECLARE_EVENT_TABLE’ with no type [-fpermissive]
hello.cpp:27:5: error: expected constructor, destructor, or type conversion before ‘wxEventTableEntry’
hello.cpp: In member function ‘virtual bool MyApp::OnInit()’:
hello.cpp:34:84: error: conversion from ‘const char [12]’ to ‘const wxString’ is ambiguous
hello.cpp:34:84: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [12]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [12]’ to ‘int’
hello.cpp:15:5: error:   initializing argument 1 of ‘MyFrame::MyFrame(const wxString&, const wxPoint&, const wxSize&)’
hello.cpp: In constructor ‘MyFrame::MyFrame(const wxString&, const wxPoint&, const wxSize&)’:
hello.cpp:43:74: error: conversion from ‘const char [17]’ to ‘const wxString’ is ambiguous
hello.cpp:43:74: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘int’
/usr/include/wx-2.8/wx/menu.h:62:17: error:   initializing argument 2 of ‘wxMenuItem* wxMenuBase::Append(int, const wxString&, const wxString&, wxItemKind)’
hello.cpp:49:40: error: conversion from ‘const char [6]’ to ‘const wxString’ is ambiguous
hello.cpp:49:40: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘int’
/usr/include/wx-2.8/wx/menu.h:62:17: error:   initializing argument 2 of ‘wxMenuItem* wxMenuBase::Append(int, const wxString&, const wxString&, wxItemKind)’
hello.cpp:49:40: error: conversion from ‘const char [6]’ to ‘const wxString’ is ambiguous
hello.cpp:49:40: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
hello.cpp:20:27: error: ISO C++ forbids declaration of ‘wxDECLARE_EVENT_TABLE’ with no type [-fpermissive]
hello.cpp:27:5: error: expected constructor, destructor, or type conversion before ‘wxEventTableEntry’
hello.cpp: In member function ‘virtual bool MyApp::OnInit()’:
hello.cpp:34:84: error: conversion from ‘const char [12]’ to ‘const wxString’ is ambiguous
hello.cpp:34:84: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [12]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [12]’ to ‘int’
hello.cpp:15:5: error:   initializing argument 1 of ‘MyFrame::MyFrame(const wxString&, const wxPoint&, const wxSize&)’
hello.cpp: In constructor ‘MyFrame::MyFrame(const wxString&, const wxPoint&, const wxSize&)’:
hello.cpp:43:74: error: conversion from ‘const char [17]’ to ‘const wxString’ is ambiguous
hello.cpp:43:74: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [17]’ to ‘int’
/usr/include/wx-2.8/wx/menu.h:62:17: error:   initializing argument 2 of ‘wxMenuItem* wxMenuBase::Append(int, const wxString&, const wxString&, wxItemKind)’
hello.cpp:49:40: error: conversion from ‘const char [6]’ to ‘const wxString’ is ambiguous
hello.cpp:49:40: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [6]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [6]’ to ‘int’
/usr/include/wx-2.8/wx/gtk/menu.h:27:18: error:   initializing argument 2 of ‘virtual bool wxMenuBar::Append(wxMenu*, const wxString&)’
hello.cpp:50:40: error: conversion from ‘const char [6]’ to ‘const wxString’ is ambiguous
hello.cpp:50:40: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [6]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [6]’ to ‘int’
/usr/include/wx-2.8/wx/gtk/menu.h:27:18: error:   initializing argument 2 of ‘virtual bool wxMenuBar::Append(wxMenu*, const wxString&)’
hello.cpp:53:44: error: conversion from ‘const char [22]’ to ‘const wxString’ is ambiguous
hello.cpp:53:44: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [22]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [22]’ to ‘int’
/usr/include/wx-2.8/wx/frame.h:110:18: error:   initializing argument 1 of ‘virtual void wxFrameBase::SetStatusText(const wxString&, int)’
hello.cpp: In member function ‘void MyFrame::OnAbout(wxCommandEvent&)’:
hello.cpp:62:66: error: conversion from ‘const char [40]’ to ‘const wxString’ is ambiguous
hello.cpp:62:66: note: candidates are:
/usr/include/wx-2.8/wx/string.h:692:3: note: wxString::wxString(wxChar, size_t) 
/usr/include/wx-2.8/wx/string.h:692:3: note:   no known conversion for argument 1 from ‘const char [40]’ to ‘wxChar {aka wchar_t}’
/usr/include/wx-2.8/wx/string.h:682:3: note: wxString::wxString(int) 
/usr/include/wx-2.8/wx/string.h:682:3: note:   no known conversion for argument 1 from ‘const char [40]’ to ‘int’
/usr/include/wx-2.8/wx/msgdlg.h:70:17: error:   initializing argument 1 of ‘int wxMessageBox(const wxString&, const wxString&, long int, wxWindow*, int, int)’
hello.cpp: In member function ‘void MyFrame::OnHello(wxCommandEvent&)’:
hello.cpp:66:47: error: cannot convert ‘const char*’ to ‘const wxChar* {aka const wchar_t*}’ for argument ‘1’ to ‘void wxLogMessage(const wxChar*, ...)’

It seems that the issues around converting from char* types to wxString types. Is there any way to resolve this? It seems strange that an official example would have all these errors, am I compiling it properly?

Answer 1

You linked to the documentation of the trunk Version of wxwidgets. In the wxstring, there were some changes since 2.8 to 3.0.

See http://docs.wxwidgets.org/trunk/overview_changes_since28.html

So i suggest you to use this page for the "Hello World" Programm. http://docs.wxwidgets.org/2.8.12/wx_helloworld.html#helloworld

I suggest you too, to use "g++" instead of "gcc". g++ links automaticlly to the libstdc++. What is the difference between g++ and gcc?