c++

How to manipulate a header and then continue with it in C#?

Hi all, I want to replace an old ISAPI filter that ran on IIS6. This filter checks if the request is of a special kind, then manipulates the header and continues with the request. Two headers are added in the manipulating method that I need for calling another special ISAPI module. So I have ISAPI C++ code like: DWORD OnPreProc(HTTP_FIL...

How to load an RSA key from binary data to an RSA structure using the OpenSSL C Library?

Currently I have my private key saved in a file, private.key, and I use the following function to load it: RSA *r = PEM_read_RSAPrivateKey("private.key", NULL, NULL, NULL); This works perfectly but I'm not happy with the file-based format; I want to save my key in pure binary form (ie, no base64 or similar) in a char* variable and load...

C++ string.substr() function problem

I want to make a program that will read some number in string format and output it like this: if the number is 12345 it should then output 12 23 34 45 . I tried using the substr() function from the c++ string library, but it gives me strange results - it outputs 1 23 345 45 instead of the expected result. Why ? #include <iostream> #incl...

using libcurl to check if a file exists on a SFTP site

I'm using C++ with libcurl to do SFTP/FTPS transfers. Before uploading a file, I need to check if the file exists without actually downloading it. If the file doesn't exist, I run into the following problems: //set up curlhandle for the public/private keys and whatever else first. curl_easy_setopt(CurlHandle, CURLOPT_URL, "sftp://user@...

Win32 API - Create Button help

I try to create 2 buttons inside my app case WM_CREATE:{ hWnd =CreateWindowEx(NULL, L"BUTTON", L"Giai PTB2", WS_TABSTOP|WS_VISIBLE| WS_CHILD|BS_DEFPUSHBUTTON, 100, 100, 100, 24, hWnd, (HMENU)IDC_PTB2_BUTTON, ...

Write set of integers to std::ofstream and be able to read them back

Hello, I need to write a bunch of unsigned integers to std::ofstream in binary mode: std::ofstream f; f.open("some path", std::ios::out | std::ios::binary); // some loop { unsigned int k = get_k(); // may product numbers from 0 to 65535 f << k; } f.close(); They are written to the output file "as is" w/o any delimiter. So when I'...

How can I find out how much memory an instance of a C++ class consumes?

Hi, I am developing a Graph-class, based on boost-graph-library. A Graph-object contains a boost-graph, so to say an adjacency_list, and a map. When monitoring the total memory usage of my program, it consumes quite a lot (checked with pmap). Now, I would like to know, how much of the memory is exactly consumed by a filled object of thi...

Why is 'volatile' parasitic in C++?

Consider the following code: int main() { int i; volatile int* p = &i; ...

Atomic swap in GNU C++

I want to verify that my understanding is correct. This kind of thing is tricky so I'm almost sure I am missing something. I have a program consisting of a real-time thread and a non-real-time thread. I want the non-RT thread to be able to swap a pointer to memory that is used by the RT thread. From the docs, my understanding is that...

reference function from another function

I forgot how to reference another function into a function in C++? In python it is declare as a class so that I can use it. double footInches(double foot) { double inches = (1.0/12.00) * foot; return inches; } double inchMeter(double inch) { double meter = 39.37 * (footInches(inch)); return meter; } I want to reference footInches...

C++ Stringstream int to string but returns null

Hi below is my function: string Employee::get_print(void) { string out_string; stringstream ss; ss << e_id << " " << type << endl; out_string = ss.str(); return out_string; } e_id and type are int and they contain values from the class Employee. But when I pass them into the stringstream they just clear the string wh...

Is it good practice to generally make heavyweight classes non-copyable?

I have a Shape class containing potentially many vertices, and I was contemplating making copy-constructor/copy-assignment private to prevent accidental needless copying of my heavyweight class (for example, passing by value instead of by reference). To make a copy of Shape, one would have to deliberately call a "clone" or "duplicate" m...

Binary Cosine Cofficient

I was given the following forumulae for calculating this sim=|Q∩D| / √|Q|√|D| I went ahed and implemented a class to compare strings consisting of a series of words #pragma once #include <vector> #include <string> #include <iostream> #include <vector> using namespace std; class StringSet { public: StringSet(void); StringSet( con...

reading a file of unknown length with a function

I'm trying to write a short function that will let me quickly read in a file of unknown size and return pointer to the array of data and the length of that array but it seems my code isn't working. What am i doing wrong? int readIn(int* pointer, param parameters, string description) { string fileName = parameters.fileName + " " + de...

How to get values of attributes on a XML file using C++ ?

Need to write some C++ code that reads XML string and if i do something like: get valueofElement("ACTION_ON_CARD") it returns 3 get valueofElement("ACTION_ON_ENVELOPE") it returns YES XML String: <ACTION_ON_CARD>3</ACTION_ON_CARD> <ACTION_ON_ENVELOPE>YES</ACTION_ON_ENVELOPE> Any code example would be helpfull Thanks ...

RAII: Initializing data member in const method

In RAII, resources are not initialized until they are accessed. However, many access methods are declared constant. I need to call a mutable (non-const) function to initialize a data member. Example: Loading from a data base struct MyClass { int get_value(void) const; private: void load_from_database(void); // Loads the ...

Compilation failing - no #include - boost

Hi, I'm trying to compile a third-party library, but g++ is complaining about the following line: typedef boost::shared_ptr<MessageConsumer> MessageConsumerPtr; The strange thing is, there is no #include directive in the file - and it is clearly supposed to be this way; there are about 60 files with the same (or very similar) issues....

Why is the volatile qualifier used through out std::atomic?

From what I've read from Herb Sutter and others you would think that volatile and concurrent programming were completely orthogonal concepts, at least as far as C/C++ are concerned. However, in GCC c++0x extension all of std::atomic's member functions have the volatile qualifier. The same is true in Anthony Williams's implementation of...

Which namespace does operator<< (stream) go to?

If I have have some overloaded ostream operators, defined for library local objects, is its okay for them to go to std namespace? If I do not declare them in std namespace, then I must use using ns:: operator <<. As a possible follow-up question, are there any operators which should go to standard or global namespace? ...

MAPI_E_NOT_FOUND on OpenMsgStore

Hi, I'm trying to open the MessageStore of a user using MAPI. The weird thing is, when I run this a console application, while I'm logged with the user, everything works fine. But when I run this as a Windows Service I get MAPI_E_NOT_FOUND when trying to open the MessageStore. I already configured the service to run as the user. Map...