I am trying to use exiftool form Cocoa
#include <iostream>
#include "ExifTool.h" // this is a .mm file so that we can include C++ code/structures
#implementation MyClass
-(id)myInit
{
if (self = [super init])
{
ExifTool* tool = new ExifTool("/Users/trygve/Tools/exiftool");
}
}
This is obviously just a test but in the "new ExifTool" line I get a crash:
dyld`dyld_fatal_error:
0x7fff5fc01074 <+0>: int3
-> 0x7fff5fc01075 <+1>: nop
Thread 1: EXC_BREAKPOINT (code=EXC_I386_BPT, subcode=0x0)
dyld: Symbol not found: __ZN8ExifToolC1EPKcS1_
The following code works fine in a straight C++ terminal program. This is from the examples on the exiftool developer page. Why does this code work fine, but when I try to use it from a Cocoa .mm file, it does not?
#include <iostream>
#include "ExifTool.h"
int main(int argc, char **argv)
{
if (argc < 2) {
std::cout << "Example1: Read metadata from an image." << std::endl;
std::cout << "Please specify input file name" << std::endl;
return 1;
}
// create our ExifTool object
ExifTool *et = new ExifTool("/Users/trygve/Tools/exiftool");
// read metadata from the image
TagInfo *info = et->ImageInfo(argv[1],NULL,5);
if (info) {
// print returned information
for (TagInfo *i=info; i; i=i->next) {
std::cout << i->name << " = " << i->value << std::endl;
}
// we are responsible for deleting the information when done
delete info;
} else if (et->LastComplete() <= 0) {
std::cerr << "Error executing exiftool!" << std::endl;
}
// print exiftool stderr messages
char *err = et->GetError();
if (err) std::cerr << err;
delete et; // delete our ExifTool object
return 0;
}
It turns out that the C++ code files associated with this were getting copied into the app rather than compiled. It works as expected. With just the header files there was no error, and a pretty cryptic crash.
Related
I am trying to get the exit code of a child process (using boost::process and boost::asio) when that child process is killed due to a segmentation violation or divide be zero or any other kill signal. The exit code and error code always return with 0 and success.
I am running this on CentOS 7 using g++ 4.8.5 and boost 1.66
If I run the same code with a child process that simply returns a non-zero exit code it successfully returns that exit code.
#include <iostream>
#include <boost/process.hpp>
#include <boost/asio/io_service.hpp>
namespace bp = boost::process;
using namespace std;
int main (int argc, char** argv)
{
string exe = "./crashes";
vector<string> data;
boost::asio::io_service ios;
int exit_code;
error_code ec;
future<string> ostr;
bp::child c(exe,
(bp::std_out & bp::std_err) > ostr,
ios,
bp::on_exit=[&exit_code, &ec](int exit, const error_code& ecin)
{exit_code = exit; ec = ecin;});
ios.run();
cout << "Exit Code = " << exit_code << endl;
cout << "Error Code = " << ec.message() << endl;
cout << "child stdin & stderr:\n";
cout << ostr.get() << endl;
return exit_code;
}
and the crashes code
int main (int argc, char** argv)
{
int* y = 0;
int c = *y;
}
The results show a 0 exit code and Success error_code
Exit Code = 0
Error Code = Success
child stdin & stderr:
running the crashes executable alone returns an exit code of 139
bash-4.2$ ./crashes
Segmentation fault (core dumped)
bash-4.2$ echo $?
139
The details of process termination and exit codes are platform dependent.
Boost process papers over the differences in the default interface: your on_exit handler is called with the result of boost::process::detail::posix::eval_exit_status() of the exit status, which means:
inline int eval_exit_status(int code)
{
if (WIFEXITED(code))
{
return WEXITSTATUS(code);
}
else if (WIFSIGNALED(code))
{
return WTERMSIG(code);
}
else
{
return code;
}
}
So, you get "exit-code 11" meaning segfault... If you want to actually know, you can look at native_exit_code()
bp::on_exit = [&result, &c](int /*ignored*/, const std::error_code &ec) {
auto exit_status = c.native_exit_code();
result.exit_code = boost::make_optional(WIFEXITED(exit_status), WEXITSTATUS(exit_status));
result.signal = boost::make_optional(WIFSIGNALED(exit_status), WTERMSIG(exit_status));
result.ec = ec;
}
Now this assumes some changes to the result variables. Full listing:
Listing
#include <boost/asio/io_service.hpp>
#include <boost/process.hpp>
#include <iostream>
namespace bp = boost::process;
int main(int argc, char**) {
std::string exe = argc>1? "./ltua" : "./crashes";
boost::asio::io_service ios;
struct {
boost::optional<int> exit_code;
boost::optional<int> signal;
std::error_code ec{};
} result;
std::future<std::string> ostr;
bp::group g;
bp::child c(exe, g, (bp::std_out & bp::std_err) > ostr, ios,
bp::on_exit = [&result, &c](int /*ignored*/, const std::error_code &ec) {
auto exit_status = c.native_exit_code();
result.exit_code = boost::make_optional(WIFEXITED(exit_status), WEXITSTATUS(exit_status));
result.signal = boost::make_optional(WIFSIGNALED(exit_status), WTERMSIG(exit_status));
result.ec = ec;
});
//g.wait();
ios.run();
if (result.exit_code) {
std::cout << "Exited with " << *result.exit_code << std::endl;
}
if (result.signal) {
std::cout << "Signaled with sginal #" << *result.signal << ", aka " << ::strsignal(*result.signal) << std::endl;
}
std::cout << "Error Code = " << result.ec.message() << std::endl;
std::cout << "child stdin & stderr:\n";
std::cout << ostr.get() << std::endl;
return result.exit_code? *result.exit_code : 255;
}
Output
When run with ltua.cpp:
#include <iostream>
int main() {
std::cout << "so long" << std::end;
std::cerr << "and thanks" << std::end;
std::cout << "for all" << std::end;
std::cerr << "the fish" << std::end;
return 42;
}
Prints
Exited with 42
Error Code = Success
child stdin & stderr:
so long
and thanks
for all
the fish
And with crashes.cpp:
int main() {
int *y = 0;
int c = *y;
}
Prints
Signaled with sginal #11, aka Segmentation fault
Error Code = Success
child stdin & stderr:
Using this msdn reference I created a small use case.
#include <iostream>
#include <windows.h>
int main()
{
const std::wstring dir_path = L"\\\\?\\c:\\temp\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory\\ThisIsPrettyLongNameForDirectory";
if (!CreateDirectoryW(dir_path.c_str(), NULL))
{
std::cout << " Error occurred while creation of directory!!! " << GetLastError() << std::endl;
}
else
{
std::cout << "Lenth is " << dir_path.length() << std::endl;
if (dir_path.length() > 255)
{
if (!SetCurrentDirectoryW(buf.c_str()))
{
std::cout << " Error occurred!!! " << GetLastError() << std::endl;
}
else
{
std::cout << " Successful!!!" << std::endl;
}
}
}
return 0;
}
However, I get the output as
Error occurred while creation of directory!!! 3
Error code 3 points me to
ERROR_PATH_NOT_FOUND
3 (0x3)
The system cannot find the path specified.
Are there any other way to use long path names in CreateDirectoryW or SetCurrentDirectoryW APIs that I am unaware of ?
PS:I am using VS 2015 Update 3 compiler on Windows 7.
You have to create each directory on the path one by one. So the parent directory to the directory you pass must exist before you call CreateDirectory.
This information can be found by reading the documentation. It specifically calls out that error code and says:
One or more intermediate directories do not exist; this function will only create the final directory in the path.
I'd like to transmit a shared_ptr object via boost asio from a client to a server. Here is my code:
#include <boost/archive/text_iarchive.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/asio.hpp>
#include <boost/serialization/export.hpp>
#include <boost/serialization/shared_ptr.hpp>
#include <chrono>
#include <iostream>
#include <sstream>
#include <string>
#include <thread>
using namespace std;
class Message {
public:
Message() {
}
virtual ~Message() {
}
string text;
private:
friend class boost::serialization::access;
template <class Archive>
void serialize(Archive &ar, const unsigned int version) {
ar &text;
}
};
BOOST_CLASS_EXPORT(Message)
void runClient() {
// Give server time to startup
this_thread::sleep_for(chrono::milliseconds(3000));
boost::asio::ip::tcp::iostream stream("localhost", "3000");
boost::archive::text_oarchive archive(stream);
for (int i = 0; i < 10; i++) {
std::shared_ptr<Message> dl = std::make_shared<Message>();
stringstream ss;
ss << "Hello " << i;
dl->text = ss.str();
archive << dl;
}
stream.close();
cout << "Client shutdown" << endl;
}
void handleIncommingClientConnection(boost::asio::ip::tcp::acceptor &acceptor) {
boost::asio::ip::tcp::iostream stream;
acceptor.accept(*stream.rdbuf());
boost::archive::text_iarchive archive(stream);
while (true) {
std::shared_ptr<Message> m;
try {
archive >> m;
cout << m->text << endl;
} catch (std::exception &ex) {
cout << ex.what() << endl;
if (stream.eof()) {
cout << "eof" << endl;
stream.close();
cout << "Server: shutdown client handling..." << endl;
break;
} else
throw ex;
}
}
}
void runServer() {
boost::asio::io_service ios;
boost::asio::ip::tcp::endpoint endpoint = boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), 3000);
boost::asio::ip::tcp::acceptor acceptor(ios, endpoint);
handleIncommingClientConnection(acceptor);
}
int main(int argc, char **argv) {
thread clientThread(runClient);
thread serverThread(runServer);
clientThread.join();
serverThread.join();
return 0;
}
Here is the program output:
Hello 0
Hello 1
Hello 2
Hello 3
Hello 3
Hello 3
Hello 3
Hello 3
Client shutdown
Hello 3
Hello 3
input stream error
eof
Server: shutdown client handling...
I am expecting the following output:
Hello 0
Hello 1
Hello 2
Hello 3
Hello 4
Hello 5
Hello 6
Hello 7
Client shutdown
Hello 8
Hello 9
input stream error
eof
Server: shutdown client handling...
When changing the shared_ptr to a simple object (std::shared_ptr<Message> m; to Message m) everything works as expected. I want to stick to the shared_ptr. What do I need to change?
Serialization alone seems to work:
stringstream stream;
{
boost::archive::text_oarchive archive(stream);
std::shared_ptr<Message> dl = std::make_shared<Message>();
stringstream ss;
ss << "Hello World!";
dl->text = ss.str();
archive << dl;
}
{
boost::archive::text_iarchive archive(stream);
std::shared_ptr<Message> m;
archive >> m;
cout << m->text << endl;
}
Output: Hello World!
The issues you're encountering are due to object tracking done by Boost.Serialization.
Depending on how the class is used and other factors, serialized
objects may be tracked by memory address. This prevents the same
object from being written to or read from an archive multiple times.
These stored addresses can also be used to delete objects created
during a loading process that has been interrupted by throwing of an
exception.
The documentation actually foreshadows this specific issue happening:
This could cause problems in progams[sic] where the copies of different
objects are saved from the same address.
Furthermore, the Class Serialization Traits documentation on object tracking tells us that in this particular situation, object tracking is enabled:
Default tracking traits are:
For primitive, track_never.
For pointers, track_never. That is, addresses of addresses are not tracked by default.
All current serialization wrappers such as boost::serialization::nvp, track_never.
For all other types, track_selectively. That is addresses of serialized objects are tracked if and only if one or more of the
following is true:
an object of this type is anywhere in the program serialized through a pointer.
the class is explicitly "exported" - see below.
the class is explicitly "registered" in the archive
Going back to your situation -- in the client, due to how your loop body is written, the 5th (and following) Message instance were allocated at the same address as the 4th Message instance. You can verify this by inspecting the values of dl.get() in each iteration. (In my tests on coliru, all of the instances were allocated at the same address, so YMMV).
Due to how object tracking works, all those shared_ptr instances were considered to point to the same Message instance (even though you changed the value meanwhile -- the library does not expect this happening), so the additional occurrences were just serialized as additional references. Upon deserialization... to be honest this smells of memory leaks and/or dangling reference issues (opinion, haven't investigated this in detail).
Summed up, the main issue with the code as shown is that it breaks a prerequisite of the serialization library, which is that you're serializing some constant state, and on deserialization you recreate that same state.
One way to address this would be to have an initialized std::vector of shared_ptr<Message> containing all the messages to transmit in this particular transaction. Similarly, you'd deserialize the whole vector on the other side. If you expect to have some persistent connection, then add framing to the protocol, with each frame containing an archive that contains one sequence of messages.
Minimal code modifications to make this work -- add include
#include <boost/serialization/vector.hpp>
Change runClient() as such:
void runClient() {
// Give server time to startup
this_thread::sleep_for(chrono::milliseconds(3000));
boost::asio::ip::tcp::iostream stream("127.0.0.1", "3000");
std::vector<std::shared_ptr<Message>> messages;
for (int i = 0; i < 10; i++) {
std::shared_ptr<Message> dl = std::make_shared<Message>();
stringstream ss;
ss << "Hello " << i;
dl->text = ss.str();
messages.emplace_back(dl);
}
boost::archive::text_oarchive archive(stream);
archive << messages;
stream.close();
cout << "Client shutdown" << endl;
}
And change handleIncommingClientConnection(...) as such:
void handleIncommingClientConnection(boost::asio::ip::tcp::acceptor &acceptor) {
boost::asio::ip::tcp::iostream stream;
acceptor.accept(*stream.rdbuf());
boost::archive::text_iarchive archive(stream);
while (true) {
try {
std::vector<std::shared_ptr<Message>> messages;
archive >> messages;
for (auto const& m : messages) {
cout << m->text << endl;
}
} catch (std::exception &ex) {
cout << ex.what() << endl;
if (stream.eof()) {
cout << "eof" << endl;
stream.close();
cout << "Server: shutdown client handling..." << endl;
break;
} else
throw ex;
}
}
}
NB: This doesn't add any support for multiple frames -- the client is expected to close the connection after it sent one vector of messages, otherwise the behaviour is undefined.
Sample on Coliru
Further resources:
boost serialization multiple objects
So I am using xinput with my program, it is all set up and working so I can detect my xbox one controller. I want to be able to detect when a button on the controller is pressed. The procedure I use works if I hold down the button when the program starts. I have the if command setup inside a while so it constantly executes although for some reason the value does not change when I press A on my controller.
So basically, if I hold down A when the program is opening it works and returns the cout on the screen. Although if I want to press it a little after the program has started (which is what I want to work) it does not detect it.
Here is my code:
using namespace std;
XINPUT_STATE state;
bool A_button_pressed;
int online;
int test;
int main() {
if (XInputGetState(0, &state) == ERROR_SUCCESS)
{
online = 1;
cout << "I could find a controller, it is an Xbox Controller" << endl;
} else {
online = 2;
cout << "Unable to find controller, searching..." << endl;
}
cout << A_button_pressed << endl;
cout << "Active" << endl;
while (online == 1) {
bool A_button_pressed = ((state.Gamepad.wButtons & XINPUT_GAMEPAD_A) != 0);
cout << A_button_pressed << endl;
if (A_button_pressed = ((state.Gamepad.wButtons & XINPUT_GAMEPAD_A) != 0)) {
cout << "You pressed a button, congrats, game over..." << endl;
}
};
}
As far as I know I am including all of the correct libraries in the correct order:
#include "stdafx.h"
#include <windows.h>
#include <iostream>
#include <Xinput.h>
#pragma comment(lib, "Xinput.lib")
#pragma comment(lib, "Xinput9_1_0.lib")
Your problem is that you are only calling XInputGetState once at startup. You must call XInputGetState every frame that your program runs so that your state info can be updated.
i have written this small piece of Code for testing purposes:
#include <iostream>
#include "SDL2/SDL.h"
int main(int argc, char* argv[]) {
if (SDL_Init(SDL_INIT_EVERYTHING) != 0) {
printf("Unable to initialize SDL: %s\n", SDL_GetError());
return 1;
}
// Betriebssystem ermitteln
std::string PlatFormString;
PlatFormString = SDL_GetPlatform();
std::cout << PlatFormString << "\n";
// Separator ermitteln
char Separator = '/';
if (PlatFormString == "Windows") {
Separator = '\\';
}
std::cout << "Separator: " << Separator << "\n";
// Installationspfad ermitteln
std::string InstallPath;
InstallPath = SDL_GetBasePath();
std::cout << InstallPath << "\n";
// Benutzerverzeichnis ermitteln
char* UserPath;
UserPath = SDL_GetPrefPath("TFF", "Blaster");
if (UserPath == nullptr) {
std::cout << "No Userpath aviable !! \n";
}
else {
std::cout << UserPath << "\n";
}
SDL_Quit();
return 0;
};
Under Linux eerthing works fine.
But under Windows, i am getting these strange errors ...
-------------- Build: Debug in Test (compiler: GNU GCC Compiler)---------------
g++.exe -LD:\mingw64 -LD:\mingw64\bin -LD:\mingw64\include -LD:\mingw64\include\SDL2 -LD:\mingw64\lib -o bin\Debug\Test.exe obj\Debug\src\Test.o -lmingw32 -lSDL2main -lSDL2 -lSDL2_image -lSDL2_mixer ..\..\mingw64\lib\libSDL2main.a ..\..\mingw64\lib\libSDL2.a
..\..\mingw64\lib\libSDL2.a(SDL_systimer.o): In function `timeSetPeriod':
/Users/slouken/release/SDL/SDL2-2.0.3-source/foo-x64/../src/timer/windows/SDL_systimer.c:58: undefined reference to `__imp_timeBeginPeriod'
/Users/slouken/release/SDL/SDL2-2.0.3-source/foo-x64/../src/timer/windows/SDL_systimer.c:52: undefined reference to `__imp_timeEndPeriod'
/Users/slouken/release/SDL/SDL2-2.0.3-source/foo-x64/../src/timer/windows/SDL_systimer.c:58: undefined reference to `__imp_timeBeginPeriod'
and so on. I dont know whats going on there. Can anyone help ?
I#m using Codeblocks 13.12, minGW64 (4.8.1), SDL 2.0.3 and Windows 7 64bit
You need to link against winmm.lib.
Try adding
#pragma comment(lib, "winmm.lib")
to your source.
I am posting this about a year later but for the future searchers here is the solution. Replace libSDL2.a with libSDL2.dll.a and it will compile just fine. The issue has something to do with dynamic and static linking with a windows machine or something I personally do I understand it completely but it works.
I came across the solution by reading this article: http://tech.yipp.ca/sdl/how-to-fix-libsdla-undefined-reference/
However this goes on a whole other solution I read between the lines or more particularly.
This is a really a rare problem that would occur only when you try to link with libSDL.a static library instead of the dynamic library SDL.dll. Then you have to add those library that SDL.dll normally links against which are the three above.