C Convert string or char to wstring or wchar t

Question

string s           wstring ws   FUNCTION s  ws     How would i assign the contents of s to ws   Searched google and used some techniques but they can t assign the exact content  The content is distorted

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Your question is underspecified  Strictly  that example is a syntax error  However  mbstowcs is probably what you re looking for  It is a C-library function and operates on buffers  but here s an easy-to-use idiom  courtesy of Mooing Duck  std  wstring ws s size    L         Overestimate number of code points  ws resize   mbstowcs s  amp ws 0   ws size    s c str    s size         Shrink to fit

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Here s a way to combining string  wstring and mixed string constants to wstring  Use the wstringstream class   This does NOT work for multi-byte character encodings  This is just a dumb way of throwing away type safety and expanding 7 bit characters from std  string into the lower 7 bits of each character of std wstring  This is only useful if you have a 7-bit ASCII strings and you need to call an API that requires wide strings    include  lt sstream gt   std  string narrow    narrow   std  wstring wide   L wide    std  wstringstream cls  cls  lt  lt    abc    lt  lt  narrow c str    lt  lt  L  def    lt  lt  wide c str    std  wstring total  cls str

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string s           is an error   You should use wstring directly   wstring ws   L

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use this code to convert your string to wstring  std  wstring string2wString const std  string amp  s       int len      int slength    int s length     1      len   MultiByteToWideChar CP ACP  0  s c str    slength  0  0        wchar t  buf   new wchar t len       MultiByteToWideChar CP ACP  0  s c str    slength  buf  len       std  wstring r buf       delete   buf      return r     int main        std  wstring str  your string       std  wstring wStr string2wString str       return 0

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Here is my super basic solution that might not work for everyone  But would work for a lot of people  It requires usage of the Guideline Support Library  Which is a pretty official C   library that was designed by many C   committee authors   https   github com isocpp CppCoreGuidelines https   github com Microsoft GSL      std  string to string std  wstring const  amp  wStr                std  string temp                for  wchar t const  amp  wCh   wStr                           If the string can t be converted gsl  narrow will throw             temp push back gsl  narrow lt char gt  wCh                       return temp         All my function does is allow the conversion if possible  Otherwise throw an exception  Via the usage of gsl  narrow  https   github com isocpp CppCoreGuidelines blob master CppCoreGuidelines md es49-if-you-must-use-a-cast-use-a-named-cast

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using Boost Locale   ws   boost  locale  conv  utf to utf lt wchar t gt  s

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This variant of it is my favourite in real life  It converts the input  if it is valid UTF-8  to the respective wstring  If the input is corrupted  the wstring is constructed out of the single bytes  This is extremely helpful if you cannot really be sure about the quality of your input data   std  wstring convert const std  string amp  input        try               std  wstring convert lt std  codecvt utf8 utf16 lt wchar t gt  gt  converter          return converter from bytes input             catch std  range error amp  e                size t length   input length            std  wstring result          result reserve length           for size t i   0  i  lt  length  i                          result push back input i   amp  0xFF                     return result

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If you have QT and if you are lazy to implement a function and stuff you can use std  string str  QString str  toStdWString

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std  string - gt  wchar t   with safe mbstowcs s function  auto ws   std  make unique lt wchar t   gt  s size     1   mbstowcs s nullptr  ws get    s size     1  s c str    s size      This is from my sample code

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If you are using Windows Visual Studio and need to convert a string to wstring you could use    include  lt AtlBase h gt   include  lt atlconv h gt      string s    some string   CA2W ca2w s c str     wstring w   ca2w  printf   s    ls   s c str    w c str       Same procedure for converting a wstring to string  sometimes you will need to specify a codepage     include  lt AtlBase h gt   include  lt atlconv h gt      wstring w   L some wstring   CW2A cw2a w c str     string s   cw2a  printf   s    ls   s c str    w c str       You could specify a codepage and even UTF8  that s pretty nice when working with JNI Java   A standard way of converting a std  wstring to utf8 std  string is showed in this answer          using ATL CA2W ca2w str  CP UTF8           or the standard way taken from the answer above  include  lt codecvt gt   include  lt string gt      convert UTF-8 string to wstring std  wstring utf8 to wstring  const std  string amp  str        std  wstring convert lt std  codecvt utf8 lt wchar t gt  gt  myconv      return myconv from bytes str         convert wstring to UTF-8 string std  string wstring to utf8  const std  wstring amp  str        std  wstring convert lt std  codecvt utf8 lt wchar t gt  gt  myconv      return myconv to bytes str       If you want to know more about codepages there is an interesting article on Joel on Software  The Absolute Minimum Every Software Developer Absolutely  Positively Must Know About Unicode and Character Sets    These CA2W  Convert Ansi to Wide unicode  macros are part of ATL and MFC String Conversion Macros  samples included    Sometimes you will need to disable the security warning  4995   I don t know of other workaround  to me it happen when I compiled for WindowsXp in VS2012     pragma warning push   pragma warning disable  4995   include  lt AtlBase h gt   include  lt atlconv h gt   pragma warning pop    Edit  Well  according to this article the article by Joel appears to be   while entertaining  it is pretty light on actual technical details   Article  What Every Programmer Absolutely  Positively Needs To Know About Encoding And Character Sets To Work With Text

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Assuming that the input string in your example        is a UTF-8 encoded  which it isn t  by the looks of it  but let s assume it is for the sake of this explanation  -   representation of a Unicode string of your interest  then your problem can be fully solved with the standard library  C  11 and newer  alone   The TL DR version    include  lt locale gt   include  lt codecvt gt   include  lt string gt   std  wstring convert lt std  codecvt utf8 utf16 lt wchar t gt  gt  converter  std  string narrow   converter to bytes wide utf16 source string   std  wstring wide   converter from bytes narrow utf8 source string     Longer online compilable and runnable example    They all show the same example  There are just many for redundancy       http   ideone com KA1oty http   ide geeksforgeeks org 5pRLSh http   rextester com DIJZK52174   Note  old    As pointed out in the comments and explained in https   stackoverflow com a 17106065 6345 there are cases when using the standard library to convert between UTF-8 and UTF-16 might give unexpected differences in the results on different platforms  For a better conversion  consider std  codecvt utf8 as described on http   en cppreference com w cpp locale codecvt utf8  Note  new    Since the codecvt header is deprecated in C  17  some worry about the solution presented in this answer were raised  However  the C   standards committee added an important statement in http   www open-std org jtc1 sc22 wg21 docs papers 2017 p0618r0 html saying     this library component should be retired to Annex D  along side   until a suitable replacement is standardized    So in the foreseeable future  the codecvt solution in this answer is safe and portable

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Windows API only  pre C  11 implementation  in case someone needs it    include  lt stdexcept gt   include  lt vector gt   include  lt windows h gt   using std  runtime error  using std  string  using std  vector  using std  wstring   wstring utf8toUtf16 const string  amp  str       if  str empty          return wstring        size t charsNeeded     MultiByteToWideChar CP UTF8  0         str data     int str size    NULL  0      if  charsNeeded    0        throw runtime error  Failed converting UTF-8 string to UTF-16        vector lt wchar t gt  buffer charsNeeded      int charsConverted     MultiByteToWideChar CP UTF8  0         str data     int str size     amp buffer 0   buffer size        if  charsConverted    0        throw runtime error  Failed converting UTF-8 string to UTF-16        return wstring  amp buffer 0   charsConverted

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int StringToWString std  wstring  amp ws  const std  string  amp s        std  wstring wsTmp s begin    s end          ws   wsTmp       return 0

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method s2ws works well  Hope helps   std  wstring s2ws const std  string amp  s        std  string curLocale   setlocale LC ALL            const char   Source   s c str        size t  Dsize   mbstowcs NULL   Source  0    1      wchar t   Dest   new wchar t  Dsize       wmemset  Dest  0   Dsize       mbstowcs  Dest  Source  Dsize       std  wstring result    Dest      delete    Dest      setlocale LC ALL  curLocale c str         return result

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String to wstring  std  wstring Str2Wstr const std  string amp  str        int size needed   MultiByteToWideChar CP UTF8  0   amp str 0    int str size    NULL  0       std  wstring wstrTo size needed  0       MultiByteToWideChar CP UTF8  0   amp str 0    int str size     amp wstrTo 0   size needed       return wstrTo      wstring to String  std  string Wstr2Str const std  wstring amp  wstr        typedef std  codecvt utf8 lt wchar t gt  convert typeX      std  wstring convert lt convert typeX  wchar t gt  converterX      return converterX to bytes wstr

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Based upon my own testing  On windows 8  vs2010  mbstowcs can actually damage original string  it works only with ANSI code page  If MultiByteToWideChar WideCharToMultiByte can also cause string corruption - but they tends to replace characters which they don t know with     question marks  but mbstowcs tends to stop when it encounters unknown character and cut string at that very point   I have tested Vietnamese characters on finnish windows    So prefer Multi -windows api function over analogue ansi C functions   Also what I ve noticed shortest way to encode string from one codepage to another is not use MultiByteToWideChar WideCharToMultiByte api function calls but their analogue ATL macros  W2A   A2W   So analogue function as mentioned above would sounds like   wstring utf8toUtf16 const string  amp  str       USES CONVERSION      acp   CP UTF8     return A2W  str c str           acp is declared in USES CONVERSION macro   Or also function which I often miss when performing old data conversion to new one   string ansi2utf8  const string amp  s        USES CONVERSION      acp   CP ACP     wchar t  pw   A2W  s c str           acp   CP UTF8     return W2A  pw        But please notice that those macro s use heavily stack - don t use for loops or recursive loops for same function - after using W2A or A2W macro - better to return ASAP  so stack will be freed from temporary conversion

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From char  to wstring   char  str    hello worlddd   wstring wstr  str  str strlen str      From string to wstring   string str    hello worlddd   wstring wstr  str begin    str end       Note this only works well if the string being converted contains only ASCII characters

[c++] C++ Convert string (or char) to wstring (or wchar_t)

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[c++] C++ Convert string (or char*) to wstring (or wchar_t*)

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[c++] C++ Convert string (or char) to wstring (or wchar_t)