How to convert std::string to LPCSTR?

My 정리 :

std::string s2 = (LPSTR)pcds->lpData;

To "convert" a std::string to a LPCSTR depends on the exact context but usually calling .c_str() is sufficient.

This works.

void TakesString(LPCSTR param);

void f(const std::string& param)
{
    TakesString(param.c_str());
}

Note that you shouldn't attempt to do something like this.

LPCSTR GetString()
{
    std::string tmp("temporary");
    return tmp.c_str();
}

The buffer returned by .c_str() is owned by the std::string instance and will only be valid until the string is next modified or destroyed.

정의 -----------------------

LPSTR - (long) pointer to string - char *

LPCSTR - (long) pointer to constant string - const char *

LPWSTR - (long) pointer to Unicode (wide) string - wchar_t *

LPCWSTR - (long) pointer to constant Unicode (wide) string - const wchar_t *

LPTSTR - (long) pointer to TCHAR (Unicode if UNICODE is defined, ANSI if not) string - TCHAR *

LPCTSTR - (long) pointer to constant TCHAR string - const TCHAR *

std:string 정의 페이지

http://www.cplusplus.com/reference/string/string/

원본 페이지 :

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from: http://stackoverflow.com/questions/1200188/how-to-convert-stdstring-to-lpcstr

64down votefavorite 28	How can I convert a std::string to LPCSTR? Also, how can I convert a std::string to LPWSTR? I am totally confused with these LPCSTR LPSTR LPWSTR LPCWSTR? Are LPWSTR and LPCWSTR are the same? c++ windows string shareimprove this question edited Jul 29 '09 at 16:59 Don Wakefield 4,91211945 asked Jul 29 '09 at 13:18 Cute 2,596186693
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8 Answers

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up vote58down voteaccepted	str.c_str() gives you a const char *, which is an LPCSTR (Long Pointer to Constant STRing) -- means that it's a pointer to a 0 terminated string of characters. W means wide string (composed of wchar_t instead of char). shareimprove this answer edited Jun 11 '14 at 11:19 rubenvb 31.7k774148 answered Jul 29 '09 at 13:21 Lou Franco 52.5k875131
	4   Minor picky point: on x64 LPCSTR would be a 64-bit pointer to a (constant) null-terminated string. –  Joel Jul 30 '09 at 14:41 1   the C in LPCSTR stand for const not C –  mathk Jan 30 '13 at 9:14 add a comment

up vote103down vote

Call c_str() to get a const char * (LPCSTR) from a std::string. It's all in the name: LPSTR - (long) pointer to string - char * LPCSTR - (long) pointer to constant string - const char * LPWSTR - (long) pointer to Unicode (wide) string - wchar_t * LPCWSTR - (long) pointer to constant Unicode (wide) string - const wchar_t * LPTSTR - (long) pointer to TCHAR (Unicode if UNICODE is defined, ANSI if not) string - TCHAR * LPCTSTR - (long) pointer to constant TCHAR string - const TCHAR * You can ignore the L (long) part of the names -- it's a holdover from 16-bit Windows. shareimprove this answer edited Jan 25 '13 at 17:53 oleksii 18.9k33483 answered Jul 29 '09 at 13:22 Nick Meyer 15.9k63960

3   +1 Make it very easy. –  Sauron Jul 29 '09 at 13:24 Thank u very Much for ur support –  Cute Jul 29 '09 at 13:39 add a comment

up vote25down vote

These are Microsoft defined typedefs which correspond to: LPCSTR: pointer to null terminated const string of char LPSTR: pointer to null terminated char string of char (often a buffer is passed and used as an 'output' param) LPCWSTR: pointer to null terminated string of const wchar_t LPWSTR: pointer to null terminated string of wchar_t (often a buffer is passed and used as an 'output' param) To "convert" a std::string to a LPCSTR depends on the exact context but usually calling .c_str() is sufficient. This works. void TakesString(LPCSTR param); void f(const std::string& param) { TakesString(param.c_str()); } Note that you shouldn't attempt to do something like this. LPCSTR GetString() { std::string tmp("temporary"); return tmp.c_str(); } The buffer returned by .c_str() is owned by the std::string instance and will only be valid until the string is next modified or destroyed. To convert a std::string to a LPWSTR is more complicated. Wanting an LPWSTR implies that you need a modifiable buffer and you also need to be sure that you understand what character encodingthe std::string is using. If the std::string contains a string using the system default encoding (assuming windows, here), then you can find the length of the required wide character buffer and perform the transcoding using MultiByteToWideChar (a Win32 API function). e.g. void f(const std:string& instr) { // Assumes std::string is encoded in the current Windows ANSI codepage int bufferlen = ::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), NULL, 0); if (bufferlen == 0) { // Something went wrong. Perhaps, check GetLastError() and log. return; } // Allocate new LPWSTR - must deallocate it later LPWSTR widestr = new WCHAR[bufferlen + 1]; ::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), widestr, bufferlen); // Ensure wide string is null terminated widestr[bufferlen] = 0; // Do something with widestr delete[] widestr; } shareimprove this answer edited Jul 29 '09 at 14:19 answered Jul 29 '09 at 13:28 Charles Bailey 282k42396497

How to Convert std::String to LPWSTR ??? –  Cute Jul 29 '09 at 13:44 Scholar and a gentleman! –  Russbear Aug 2 '11 at 22:02 add a comment

up vote7down vote

Using LPWSTR you could change contents of string where it points to. Using LPCWSTR you couldn't change contents of string where it points to. std::string s = SOME_STRING; // get temporary LPSTR (not really safe) LPSTR pst = &s[0]; // get temporary LPCSTR (pretty safe) LPCSTR pcstr = s.c_str(); // convert to std::wstring std::wstring ws; ws.assign( s.begin(), s.end() ); // get temporary LPWSTR (not really safe) LPWSTR pwst = &ws[0]; // get temporary LPCWSTR (pretty safe) LPCWSTR pcwstr = ws.c_str(); LPWSTR is just a pointer to original string. You shouldn't return it from function using the sample above. To get not temporary LPWSTR you should made a copy of original string on the heap. Check the sample below: LPWSTR ConvertToLPWSTR( const std::string& s ) { LPWSTR ws = new wchar_t[s.size()+1]; // +1 for zero at the end copy( s.begin(), s.end(), ws ); ws[s.size()] = 0; // zero at the end return ws; } void f() { std::string s = SOME_STRING; LPWSTR ws = ConvertToLPWSTR( s ); // some actions delete[] ws; // caller responsible for deletion } shareimprove this answer edited Jul 29 '09 at 18:13 answered Jul 29 '09 at 16:28 Kirill V. Lyadvinsky 52.1k1384168

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up vote3down vote

The MultiByteToWideChar answer that Charles Bailey gave is the correct one. Because LPCWSTR is just a typedef for const WCHAR*, widestr in the example code there can be used wherever a LPWSTR is expected or where a LPCWSTR is expected. One minor tweak would be to use std::vector<WCHAR> instead of a manually managed array: // using vector, buffer is deallocated when function ends std::vector<WCHAR> widestr(bufferlen + 1); ::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), &widestr[0], bufferlen); // Ensure wide string is null terminated widestr[bufferlen] = 0; // no need to delete; handled by vector Also, if you need to work with wide strings to start with, you can use std::wstring instead of std::string. If you want to work with the Windows TCHAR type, you can use std::basic_string<TCHAR>. Converting from std::wstring to LPCWSTR or from std::basic_string<TCHAR> to LPCTSTR is just a matter of calling c_str. It's when you're changing between ANSI and UTF-16 characters that MultiByteToWideChar (and its inverse WideCharToMultiByte) comes into the picture. shareimprove this answer edited Jul 29 '09 at 18:07 answered Jul 29 '09 at 18:00 Joel 34214

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up vote2down vote	The conversion is simple: std::string str; LPCSTR lpcstr = str.c_str(); shareimprove this answer answered Jul 29 '09 at 13:21 Timbo 15.4k53059
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up vote2down vote	Converting is simple: std::string myString; LPCSTR lpMyString = myString.c_str(); One thing to be careful of here is that c_str does not return a copy of myString, but just a pointer to the character string that std::string wraps. If you want/need a copy you'll need to make one yourself using strcpy. shareimprove this answer answered Jul 29 '09 at 13:29 Nick Haddad 4,62911833
	How to Convert std::String to LPWSTR ??? –  Cute Jul 29 '09 at 13:44 add a comment

up vote1down vote

The easiest way to convert a std::string to a LPWSTR is in my opinion: Convert the std::string to a std::vector<wchar_t> Take the address of the first wchar_t in the vector. std::vector<wchar_t> has a templated ctor which will take two iterators, such as the std::string.begin() and .end() iterators. This will convert each char to a wchar_t, though. That's only valid if the std::string contains ASCII or Latin-1, due to the way Unicode values resemble Latin-1 values. If it contains CP1252 or characters from any other encoding, it's more complicated. You'll then need to convert the characters.