This is an exercise that I want to implement in real code
I send a signal to my app (x86-64 linux). My app then executes code that walks the stack and prints out instruction pointers. I'm not sure if I want only the last few or everything to main. Anyway, I'm releasing an optimized binary without debug information. I strip symbols before its distributed.
I was wondering, how do I translate it back? I don't need to translate it in the app. I can use the machine I build to go from rip's to functions. I was thinking maybe I should also distribute one with debug information and maybe have the user be able to see the function+line but I think line will be unlikely if its optimized well
Another problem I have is my code doesn't seem to walk past the signal function. backtrace figures it out but I'm trying to do this without libc. Here's some code
#include <signal.h>
#include <cstdio>
typedef unsigned long long u64;
int mybacktrace();
#include <execinfo.h>
#include <unistd.h>
void print_stacktrace(void) {
size_t size;
enum Constexpr { MAX_SIZE = 1024 };
void *array[MAX_SIZE];
size = backtrace(array, MAX_SIZE);
backtrace_symbols_fd(array, size, STDOUT_FILENO);
}
void mysig(int signo) {
mybacktrace();
_exit(1);
}
int mybacktrace() {
u64*p;
p = (u64*)((u64)&p + 16); //seems to work correctly
for (int i = 0; i < 10 && (u64)p >= 1<<16; i++)
{
printf("%d %p\n", i, p[1]);
p = (u64*)(p[0]);
}
print_stacktrace(); return 0;
return 0;
}
int test()
{
return mybacktrace();
}
int main(int argc, char *argv[])
{
signal(SIGILL, mysig);
test();
__builtin_trap();
return 0;
}
I'm trying to run the code demo for ICU4C bellow, and getting
warning: implicit declaration of function 'austrdup'
which subsequently generate an error. I understand that this is due to the missing imported library that contains 'austrdup' function, and have been looking at the source code to guess which one it is, but no luck. Does anyone have any idea which one should be imported?
#include <unicode/umsg.h>
#include <unicode/ustring.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char const *argv[])
{
UChar* str;
UErrorCode status = U_ZERO_ERROR;
UChar *result = NULL;
UChar pattern[100];
int32_t resultlength, resultLengthOut, i;
double testArgs[] = { 100.0, 1.0, 0.0};
str=(UChar*)malloc(sizeof(UChar) * 10);
u_uastrcpy(str, "MyDisk");
u_uastrcpy(pattern, "The disk {1} contains {0,choice,0#no files|1#one file|1<{0,number,integer} files}");
for(i=0; i<3; i++){
resultlength=0;
resultLengthOut=u_formatMessage( "en_US", pattern, u_strlen(pattern), NULL, resultlength, &status, testArgs[i], str);
if(status==U_BUFFER_OVERFLOW_ERROR){ //check if output truncated
status=U_ZERO_ERROR;
resultlength=resultLengthOut+1;
result=(UChar*)malloc(sizeof(UChar) * resultlength);
u_formatMessage( "en_US", pattern, u_strlen(pattern), result, resultlength, &status, testArgs[i], str);
}
printf("%s\n", austrdup(result) ); //austrdup( a function used to convert UChar* to char*)
free(result);
}
return 0;
}
austrdup is not an official ICU method. It's only used by tests in ICU and defined in icu4c/source/test/cintltst/cintltst.h and implemented in icu4c/source/test/cintltst/cintltst.c. It is bascially just a wrapper around u_austrcpy.
I have 3 files in my project, main.cpp, Globals.h & Globals.cpp:
main.cpp
#include "Globals.h"
int main()
{
if (setup())return 1;//If setup fails terminate the program
CenterOrigin(playerSprite);
while (window.isOpen())
{
deltaTime = deltaClock.restart().asSeconds();
while (window.pollEvent(ev))
{
if (ev.type == sf::Event::Closed)window.close();
}
float rotSpeed = 5;
window.clear(sf::Color(12, 14, 12, 0.9 * 255));
window.display();
}
return 0;
}
Globals.h
#pragma once
#include <iostream>
#include <SFML/Graphics.hpp>
#include <SFML/Window.hpp>
#include <SFML/System.hpp>
#define TITLE "Belty McBelth"
#define WIDTH 1280
#define HEIGHT 720
sf::RenderWindow window;
sf::Font font;
sf::Event ev;
sf::Texture playerTex;
sf::Sprite playerSprite;
sf::Texture tieTex;
sf::Sprite tieSprite;
sf::Clock deltaClock;
float deltaTime; //Time since last frame in seconds
int setup();
void CenterOrigin(sf::Sprite & t);
Globals.cpp
#include "Globals.h"
int setup()
{
window.create(sf::VideoMode(WIDTH, HEIGHT), "Belty McBelth", sf::Style::Close);
if (!font.loadFromFile("../comic.ttf"))return 1;
if (!playerTex.loadFromFile("../PLAYER.png"))return 1;
playerSprite = sf::Sprite(playerTex);
std::cout << "Setup completed without errors \n";
return 0;
}
void CenterOrigin(sf::Sprite & t)
{
sf::FloatRect d = t.getLocalBounds();
t.setOrigin(d.width / 2, d.height / 2);
}
Whenever I try to build this project, I get a plethora of LNK2005 errors, one for each variable that is declared in the globals header file. I have searched for a solution to this problem, however I am not able to find one. I have ensured that there are no definitions in the globals.h file, however, I am still unable to build the project.
This problem solves itself if I move all the definitions into the .h file, however, through the microsoft page for the lnk2005 error, I have found that this is only because there is only one file that includes the globals header file.
Sidenote, is there any better way of handling global variables/functions? Extern is an option, but it gets too cumbersome when you have a lot of global variables.
The question is in the title. Need help figuring out why my code compiles but doesn't work as intended. Thanks!
//This example demonstrates how to do vector<string> to vectro<int> conversion using a function.
#include <iostream>
#include <string>
#include <vector>
#include <sstream>
using namespace std;
vector<int>* convertStringVectorToIntVector (vector<string> *vectorOfStrings)
{
vector<int> *vectorOfIntegers = new vector<int>;
int x;
for (int i=0; i<vectorOfStrings->size(); i++)
{
stringstream str(vectorOfStrings->at(i));
str >> x;
vectorOfIntegers->push_back(x);
}
return vectorOfIntegers;
}
int main(int argc, char* argv[]) {
//Initialize test vector to use for conversion
vector<string> *vectorOfStringTypes = new vector<string>();
vectorOfStringTypes->push_back("1");
vectorOfStringTypes->push_back("10");
vectorOfStringTypes->push_back("100");
delete vectorOfStringTypes;
//Initialize target vector to store conversion result
vector<int> *vectorOfIntTypes;
vectorOfIntTypes = convertStringVectorToIntVector(vectorOfStringTypes);
//Test if conversion is successful and the new vector is open for manipulation
int sum = 0;
for (int i=0; i<vectorOfIntTypes->size(); i++)
{
sum+=vectorOfIntTypes->at(i);
cout<<sum<<endl;
}
delete vectorOfIntTypes;
cin.get();
return 0;
}
The code above has only one problem: You are deleting your vectorOfStringTypes before you pass it to your conversion function.
Move the line delete vectorOfStringTypes; to after you have called your convert function and the program works as intended.
Can someone please post a simple code that would convert,
System::String^
To,
C++ std::string
I.e., I just want to assign the value of,
String^ originalString;
To,
std::string newString;
Don't roll your own, use these handy (and extensible) wrappers provided by Microsoft.
For example:
#include <msclr\marshal_cppstd.h>
System::String^ managed = "test";
std::string unmanaged = msclr::interop::marshal_as<std::string>(managed);
You can easily do this as follows
#include <msclr/marshal_cppstd.h>
System::String^ xyz="Hi boys";
std::string converted_xyz=msclr::interop::marshal_as< std::string >( xyz);
Check out System::Runtime::InteropServices::Marshal::StringToCoTaskMemUni() and its friends.
Sorry can't post code now; I don't have VS on this machine to check it compiles before posting.
This worked for me:
#include <stdlib.h>
#include <string.h>
#include <msclr\marshal_cppstd.h>
//..
using namespace msclr::interop;
//..
System::String^ clrString = (TextoDeBoton);
std::string stdString = marshal_as<std::string>(clrString); //String^ to std
//System::String^ myString = marshal_as<System::String^>(MyBasicStirng); //std to String^
prueba.CopyInfo(stdString); //MyMethod
//..
//Where: String^ = TextoDeBoton;
//and stdString is a "normal" string;
Here are some conversion routines I wrote many years ago for a c++/cli project, they should still work.
void StringToStlWString ( System::String const^ s, std::wstring& os)
{
String^ string = const_cast<String^>(s);
const wchar_t* chars = reinterpret_cast<const wchar_t*>((Marshal::StringToHGlobalUni(string)).ToPointer());
os = chars;
Marshal::FreeHGlobal(IntPtr((void*)chars));
}
System::String^ StlWStringToString (std::wstring const& os) {
String^ str = gcnew String(os.c_str());
//String^ str = gcnew String("");
return str;
}
System::String^ WPtrToString(wchar_t const* pData, int length) {
if (length == 0) {
//use null termination
length = wcslen(pData);
if (length == 0) {
System::String^ ret = "";
return ret;
}
}
System::IntPtr bfr = System::IntPtr(const_cast<wchar_t*>(pData));
System::String^ ret = System::Runtime::InteropServices::Marshal::PtrToStringUni(bfr, length);
return ret;
}
void Utf8ToStlWString(char const* pUtfString, std::wstring& stlString) {
//wchar_t* pString;
MAKE_WIDEPTR_FROMUTF8(pString, pUtfString);
stlString = pString;
}
void Utf8ToStlWStringN(char const* pUtfString, std::wstring& stlString, ULONG length) {
//wchar_t* pString;
MAKE_WIDEPTR_FROMUTF8N(pString, pUtfString, length);
stlString = pString;
}
I found an easy way to get a std::string from a String^ is to use sprintf().
char cStr[50] = { 0 };
String^ clrString = "Hello";
if (clrString->Length < sizeof(cStr))
sprintf(cStr, "%s", clrString);
std::string stlString(cStr);
No need to call the Marshal functions!
UPDATE Thanks to Eric, I've modified the sample code to check for the size of the input string to prevent buffer overflow.
I spent hours trying to convert a windows form listbox ToString value to a standard string so that I could use it with fstream to output to a txt file. My Visual Studio didn't come with marshal header files which several answers I found said to use. After so much trial and error I finally found a solution to the problem that just uses System::Runtime::InteropServices:
void MarshalString ( String ^ s, string& os ) {
using namespace Runtime::InteropServices;
const char* chars =
(const char*)(Marshal::StringToHGlobalAnsi(s)).ToPointer();
os = chars;
Marshal::FreeHGlobal(IntPtr((void*)chars));
}
//this is the code to use the function:
scheduleBox->SetSelected(0,true);
string a = "test";
String ^ c = gcnew String(scheduleBox->SelectedItem->ToString());
MarshalString(c, a);
filestream << a;
And here is the MSDN page with the example:
http://msdn.microsoft.com/en-us/library/1b4az623(v=vs.80).aspx
I know it's a pretty simple solution but this took me HOURS of troubleshooting and visiting several forums to finally find something that worked.
C# uses the UTF16 format for its strings.
So, besides just converting the types, you should also be conscious about the string's actual format.
When compiling for Multi-byte Character set Visual Studio and the Win API assumes UTF8 (Actually windows encoding which is Windows-28591 ).
When compiling for Unicode Character set Visual studio and the Win API assume UTF16.
So, you must convert the string from UTF16 to UTF8 format as well, and not just convert to std::string.
This will become necessary when working with multi-character formats like some non-latin languages.
The idea is to decide that std::wstring always represents UTF16.
And std::string always represents UTF8.
This isn't enforced by the compiler, it's more of a good policy to have.
#include "stdafx.h"
#include <string>
#include <codecvt>
#include <msclr\marshal_cppstd.h>
using namespace System;
int main(array<System::String ^> ^args)
{
System::String^ managedString = "test";
msclr::interop::marshal_context context;
//Actual format is UTF16, so represent as wstring
std::wstring utf16NativeString = context.marshal_as<std::wstring>(managedString);
//C++11 format converter
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> convert;
//convert to UTF8 and std::string
std::string utf8NativeString = convert.to_bytes(utf16NativeString);
return 0;
}
Or have it in a more compact syntax:
int main(array<System::String ^> ^args)
{
System::String^ managedString = "test";
msclr::interop::marshal_context context;
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> convert;
std::string utf8NativeString = convert.to_bytes(context.marshal_as<std::wstring>(managedString));
return 0;
}
I like to stay away from the marshaller.
Using CString newString(originalString);
Seems much cleaner and faster to me. No need to worry about creating and deleting a context.
// I used VS2012 to write below code-- convert_system_string to Standard_Sting
#include "stdafx.h"
#include <iostream>
#include <string>
using namespace System;
using namespace Runtime::InteropServices;
void MarshalString ( String^ s, std::string& outputstring )
{
const char* kPtoC = (const char*) (Marshal::StringToHGlobalAnsi(s)).ToPointer();
outputstring = kPtoC;
Marshal::FreeHGlobal(IntPtr((void*)kPtoC));
}
int _tmain(int argc, _TCHAR* argv[])
{
std::string strNativeString;
String ^ strManagedString = "Temp";
MarshalString(strManagedString, strNativeString);
std::cout << strNativeString << std::endl;
return 0;
}
For me, I was getting an error with some of these messages. I have an std::string. To convert it to String^, I had to do the following String^ sysString = gcnew String(stdStr.c_str()); where sysString is a System::String^ and stdStr is an std::string. Hope this helps someone
You may have to #include <string> for this to work