This is the prologue of the header CGO generated:
#ifndef GO_CGO_PROLOGUE_H
#define GO_CGO_PROLOGUE_H
typedef signed char GoInt8;
typedef unsigned char GoUint8;
typedef short GoInt16;
typedef unsigned short GoUint16;
typedef int GoInt32;
typedef unsigned int GoUint32;
typedef long long GoInt64;
typedef unsigned long long GoUint64;
typedef GoInt64 GoInt;
typedef GoUint64 GoUint;
typedef __SIZE_TYPE__ GoUintptr;
typedef float GoFloat32;
typedef double GoFloat64;
typedef float _Complex GoComplex64;
typedef double _Complex GoComplex128;
Now, trying to compile with MSVC, which has no clue as to what __SIZE_TYPE__ is or _Complex is not going to fly. I could probably come up with an extra header that covers these discrepancies, but I don't know what else does CGO header generator has up its sleeve.
Related
I have these arrays declared globally
char str1[] = "6541254939322816220209974565477289648317";
char str2[] = "3142522751761601737419090933147067701840";
int str1_size = strlen(str1);
int str2_size = strlen(str2);
int lcs[str1_size][str2_size];
int arrows[str1_size][str2_size];
But when I access this inside a function, it gives
lcs was not declared in this scope
also
array bound is not an integer constant before ‘]’ token
int lcs[str1_size][str2_size];
What am I doing wrong here ?
First of all
int a[dim];
where dim isn't a compile-time know constant (constexpr by example) isn't C++ standard; maybe it's possible with some extension with some compiler but isn't C++ standard.
So, in your case
int lcs[str1_size][str2_size];
int arrows[str1_size][str2_size];
where str1_size and str2_size are normal (not constexpr, not const initialized with literals) variables, is an error.
If you could redefine str1_size and str2_size as follows
constexpt int str1_size = strlen(str1);
constexpr int str2_size = strlen(str2);
the lcs and arrows definition could works.
Unfortunately (1) str1 and str2 aren't constexpr and (2) std::strlen() isn't constexpr.
But if declare str1/str2 constexpr and write a constexpr alternative to std::strlen...
#include <iostream>
constexpr std::size_t lenStr (char const * str)
{
std::size_t ret{};
while ( *(str++) )
++ret;
return ret;
}
constexpr char str1[] = "6541254939322816220209974565477289648317";
constexpr char str2[] = "3142522751761601737419090933147067701840";
constexpr auto str1_size = lenStr(str1);
constexpr auto str2_size = lenStr(str2);
int lcs[str1_size][str2_size];
int arrows[str1_size][str2_size];
int main ()
{
}
Unfortunately the preceding code require C++14 (in C++11 it's impossible write so complex constexpr functions).
In C++11 you should write lenStr() in a recursive way
constexpr std::size_t lenStr (char const * str, std::size_t ret = 0u)
{ return *str ? lenStr(++str, ++ret) : ret; }
The following code produces a huge list of compiler errors:
/// Uses template recursion to bind all args
template<std::size_t N, typename... Args> class Binder
{
public:
Binder(Sqlite3StatementBase &s, std::tuple<Args...> &tup)
{
Binder<N - 1, Args...> b(s, tup);
s.bind(N + 1, std::get<N, Args...>(tup)); // Line 182
}
};
/// Specialization of Binder to end recursion at 0
template<typename... Args> class Binder<0, Args...>
{
public:
Binder(Sqlite3StatementBase &s, std::tuple<Args...> &tup)
{
s.bind(1, std::get<0, Args...>(tup));
}
};
The first batch of errors consists of:
In file included from /usr/include/c++/6/bits/unique_ptr.h:37:0,
from /usr/include/c++/6/condition_variable:43,
from /home/tony/htpc/Dev/logi/src/db/logi-db.h:22,
from /home/tony/htpc/Dev/logi/src/db/logi-sqlite.h:26,
from /home/tony/htpc/Dev/logi/src/db/logi-sqlite.cpp:24:
/usr/include/c++/6/tuple: In instantiation of ‘class std::tuple_element<1ul, std::tuple<unsigned int> >’:
/usr/include/c++/6/tuple:1228:12: recursively required from ‘class std::tuple_element<2ul, std::tuple<unsigned int, unsigned int> >’
/usr/include/c++/6/tuple:1228:12: required from ‘class std::tuple_element<3ul, std::tuple<unsigned int, unsigned int, unsigned int> >’
/usr/include/c++/6/utility:106:69: required by substitution of ‘template<long unsigned int __i, class _Tp> using __tuple_element_t = typename std::tuple_element::type [with long unsigned int __i = 3ul; _Tp = std::tuple<unsigned int, unsigned int, unsigned int>]’
/usr/include/c++/6/tuple:1270:5: required by substitution of ‘template<long unsigned int __i, class ... _Elements> constexpr std::__tuple_element_t<__i, std::tuple<_Elements ...> >&& std::get(std::tuple<_Elements ...>&&) [with long unsigned int __i = 3ul; _Elements = {unsigned int, unsigned int, unsigned int}]’
/home/tony/htpc/Dev/logi/src/db/logi-sqlite.h:182:47: required from ‘logi::Sqlite3Database::Binder<N, Args>::Binder(logi::Sqlite3Database::Sqlite3StatementBase&, std::tuple<_Elements ...>&) [with long unsigned int N = 3ul; Args = {unsigned int, unsigned int, unsigned int}]’
/home/tony/htpc/Dev/logi/src/db/logi-sqlite.h:238:71: required from ‘void logi::Sqlite3Database::Sqlite3Statement<Args>::prepare_row(logi::Sqlite3Database::Sqlite3Statement<Args>::Tup&) [with Args = {unsigned int, unsigned int, unsigned int}; logi::Sqlite3Database::Sqlite3Statement<Args>::Tup = std::tuple<unsigned int, unsigned int, unsigned int>]’
/home/tony/htpc/Dev/logi/src/db/logi-sqlite.h:231:28: required from ‘void logi::Sqlite3Database::Sqlite3Statement<Args>::execute(typename logi::Sqlite3Database::Sqlite3Statement<Args>::Parent::ArgsVector&) [with Args = {unsigned int, unsigned int, unsigned int}; typename logi::Sqlite3Database::Sqlite3Statement<Args>::Parent::ArgsVector = std::vector<std::tuple<unsigned int, unsigned int, unsigned int>, std::allocator<std::tuple<unsigned int, unsigned int, unsigned int> > >]’
/home/tony/htpc/Dev/logi/src/db/logi-sqlite.cpp:354:1: required from here
/usr/include/c++/6/tuple:1228:12: error: invalid use of incomplete type ‘class std::tuple_element<0ul, std::tuple<> >’
So it seems as if the std::get call is causing other parts of the system libraries (not directly related to std::get or std::tuple) to recursively reduce Args... to nothing, and this is happening independently of my recursion of the numerical template parameter N. Is there something I can fix in my code without fundamentally changing my approach, or is it just not possible to use std::get in a context where the tuple's template parameters are variadic?
Given an implementation of the C++14 make_index_sequence function (and its associated types), you can do what you want easily enough:
template<size_t ...indices, typename ...Args>
void binder_helper(Sqlite3StatementBase &s, std::integer_sequence<size_t, indices...>, std::tuple<Args...> &tup)
{
auto dump = {(s.bind(indices, std::get<indices>(tup)), 0)...};
}
template<typename ...Args>
void binder(Sqlite3StatementBase &s, std::tuple<Args...> &tup)
{
binder_helper(s, std::make_index_sequence<sizeof...(Args)>(), tup);
}
With C++17's fold expressions, the oddball stuff in binder_helper can be reduced to something much more reasonable:
template<size_t ...indices, typename ...Args>
void binder_helper(Sqlite3StatementBase &s, std::integer_sequence<size_t, indices...>, std::tuple<Args...> &tup)
{
(s.bind(indices, std::get<indices>(tup)), ...);
}
Note that in the latter case, the standard does not guarantee thatt the calls to s.bind will be executed in order. In the former case, because the expressions are wrapped in a braced-init-list, you're guaranteed in-order evaluation.
I am getting the following error even though it seems there are no syntax errors.
usb_libusb10.h(72): error C2146: syntax error : missing ';' before identifier 'cb'
The line where the error is generating is given below-
fnusb_iso_cb cb;
I also tried to highlighted this line by using "**" in the code.
Following is the code I am using.
#pragma once
#include <Windows.h>
#include <afxwin.h>
#include "libfreenect.h"
#include <libusb.h>
// There are a few rules: PKTS_PER_XFER * NUM_XFERS <= 1000, PKTS_PER_XFER % 8 == 0.
#if defined(__APPLE__)
#define DEPTH_PKTBUF 2048
#define VIDEO_PKTBUF 2048
#define PKTS_PER_XFER 128
#define NUM_XFERS 4
#else
#define DEPTH_PKTBUF 1920
#define VIDEO_PKTBUF 1920
#if defined(_WIN32)
#define PKTS_PER_XFER 32
#define NUM_XFERS 8
#else
#define PKTS_PER_XFER 16
#define NUM_XFERS 16
#endif
#endif
typedef struct {
libusb_context *ctx;
int should_free_ctx;
} fnusb_ctx;
typedef struct {
freenect_device *parent; //so we can go up from the libusb userdata
libusb_device_handle *dev;
int device_dead; // set to 1 when the underlying libusb_device_handle vanishes (ie, Kinect was unplugged)
int VID;
int PID;
} fnusb_dev;
typedef struct {
fnusb_dev *parent; //so we can go up from the libusb userdata
struct libusb_transfer **xfers;
uint8_t *buffer;
**fnusb_iso_cb cb;**
int num_xfers;
int pkts;
int len;
int dead;
int dead_xfers;
} fnusb_isoc_stream;
int fnusb_num_devices(fnusb_ctx *ctx);
int fnusb_list_device_attributes(fnusb_ctx *ctx, struct freenect_device_attributes** attribute_list);
int fnusb_init(fnusb_ctx *ctx, freenect_usb_context *usb_ctx);
int fnusb_shutdown(fnusb_ctx *ctx);
int fnusb_process_events(fnusb_ctx *ctx);
int fnusb_process_events_timeout(fnusb_ctx *ctx, struct timeval* timeout);
int fnusb_open_subdevices(freenect_device *dev, int index);
int fnusb_close_subdevices(freenect_device *dev);
int fnusb_start_iso(fnusb_dev *dev, fnusb_isoc_stream *strm, fnusb_iso_cb cb, unsigned char endpoint, int xfers, int pkts, int len);
int fnusb_stop_iso(fnusb_dev *dev, fnusb_isoc_stream *strm);
int fnusb_get_max_iso_packet_size(fnusb_dev *dev, unsigned char endpoint, int default_size);
int fnusb_control(fnusb_dev *dev, uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex, uint8_t *data, uint16_t wLength);
int fnusb_bulk(fnusb_dev *dev, uint8_t endpoint, uint8_t *data, int len, int *transferred);
int fnusb_num_interfaces(fnusb_dev *dev);
I am trying to build a list of linked list in my application. The list will contains unique IP addresses,and for each IP addres I have a list of applications. I am trying to build it using unordered_map to take Boost::boost::asio::ip::address as a the key and std::list as value:
#include <boost/unordered/unordered_map.hpp>
#include <iostream>
#include <list>
using namespace boost::asio::ip;
using namespace std;
typedef int ApplicationID;
typedef address IPAddress;
typedef list <ApplicationID> APP_LIST;
typedef boost::unordered::unordered_map <IPAddress, APP_LIST> USER_MAP;
USER_MAP user_map;
Later I try to get the list associated with an IP address as following:
APP_LIST *list = &user_map[ip];
But I get errors in the compilation, so could you please specify what's the problem?
Is it possible to use Boost:IPaddress as a key function?
Another question is it possible to use char[some_size] as a key value?
Error Output:
In file included from /boost/functional/hash/hash.hpp:535:0,
from /boost/functional/hash.hpp:6,
from /boost/unordered/unordered_map.hpp:21,
from ipc_module.cpp:18:
/boost/functional/hash/extensions.hpp: In member function ‘std::size_t boost::hash<T>::operator()(const T&) const [with T = boost::asio::ip::address, std::size_t = long unsigned int]’:
/boost/unordered/detail/unique.hpp:331:55: instantiated from ‘boost::unordered::detail::table_impl<Types>::value_type& boost::unordered::detail::table_impl<Types>::operator[](const key_type&) [with Types = boost::unordered::detail::map<std::allocator<std::pair<const boost::asio::ip::address, std::list<int> > >, boost::asio::ip::address, std::list<int>, boost::hash<boost::asio::ip::address>, std::equal_to<boost::asio::ip::address> >, boost::unordered::detail::table_impl<Types>::value_type = std::pair<const boost::asio::ip::address, std::list<int> >, boost::unordered::detail::table_impl<Types>::key_type = boost::asio::ip::address]’
/boost/unordered/unordered_map.hpp:1192:26: instantiated from ‘boost::unordered::unordered_map<K, T, H, P, A>::mapped_type& boost::unordered::unordered_map<K, T, H, P, A>::operator[](const key_type&) [with K = boost::asio::ip::address, T = std::list<int>, H = boost::hash<boost::asio::ip::address>, P = std::equal_to<boost::asio::ip::address>, A = std::allocator<std::pair<const boost::asio::ip::address, std::list<int> > >, boost::unordered::unordered_map<K, T, H, P, A>::mapped_type = std::list<int>, boost::unordered::unordered_map<K, T, H, P, A>::key_type = boost::asio::ip::address]’
ipc_module.cpp:175:40: instantiated from here
/boost/functional/hash/extensions.hpp:176:34: error: no matching function for call to ‘hash_value(const boost::asio::ip::address&)’
/boost/functional/hash/extensions.hpp:176:34: note: candidates are:
/boost/smart_ptr/shared_ptr.hpp:708:33: note: template<class T> std::size_t boost::hash_value(const boost::shared_ptr<T>&)
/boost/functional/hash/hash.hpp:144:24: note: std::size_t boost::hash_value(bool)
/boost/functional/hash/hash.hpp:144:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘bool’
/boost/functional/hash/hash.hpp:149:24: note: std::size_t boost::hash_value(char)
/boost/functional/hash/hash.hpp:149:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘char’
/boost/functional/hash/hash.hpp:154:24: note: std::size_t boost::hash_value(unsigned char)
/boost/functional/hash/hash.hpp:154:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘unsigned char’
/boost/functional/hash/hash.hpp:159:24: note: std::size_t boost::hash_value(signed char)
/boost/functional/hash/hash.hpp:159:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘signed char’
/boost/functional/hash/hash.hpp:164:24: note: std::size_t boost::hash_value(short int)
/boost/functional/hash/hash.hpp:164:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘short int’
/boost/functional/hash/hash.hpp:169:24: note: std::size_t boost::hash_value(short unsigned int)
/boost/functional/hash/hash.hpp:169:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘short unsigned int’
/boost/functional/hash/hash.hpp:174:24: note: std::size_t boost::hash_value(int)
/boost/functional/hash/hash.hpp:174:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘int’
/boost/functional/hash/hash.hpp:179:24: note: std::size_t boost::hash_value(unsigned int)
/boost/functional/hash/hash.hpp:179:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘unsigned int’
/boost/functional/hash/hash.hpp:184:24: note: std::size_t boost::hash_value(long int)
/boost/functional/hash/hash.hpp:184:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘long int’
/boost/functional/hash/hash.hpp:189:24: note: std::size_t boost::hash_value(long unsigned int)
/boost/functional/hash/hash.hpp:189:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘long unsigned int’
/boost/functional/hash/hash.hpp:195:24: note: std::size_t boost::hash_value(wchar_t)
/boost/functional/hash/hash.hpp:195:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘wchar_t’
/boost/functional/hash/hash.hpp:202:24: note: std::size_t boost::hash_value(boost::long_long_type)
/boost/functional/hash/hash.hpp:202:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘boost::long_long_type {aka long long int}’
/boost/functional/hash/hash.hpp:207:24: note: std::size_t boost::hash_value(boost::ulong_long_type)
/boost/functional/hash/hash.hpp:207:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘boost::ulong_long_type {aka long long unsigned int}’
/boost/functional/hash/hash.hpp:215:36: note: template<class T> std::size_t boost::hash_value(T* const&)
/boost/functional/hash/hash.hpp:308:24: note: template<class T, unsigned int N> std::size_t boost::hash_value(const T (&)[N])
/boost/functional/hash/hash.hpp:314:24: note: template<class T, unsigned int N> std::size_t boost::hash_value(T (&)[N])
/boost/functional/hash/hash.hpp:327:24: note: std::size_t boost::hash_value(float)
/boost/functional/hash/hash.hpp:327:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘float’
/boost/functional/hash/hash.hpp:332:24: note: std::size_t boost::hash_value(double)
/boost/functional/hash/hash.hpp:332:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘double’
/boost/functional/hash/hash.hpp:337:24: note: std::size_t boost::hash_value(long double)
/boost/functional/hash/hash.hpp:337:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘long double’
/boost/functional/hash/hash.hpp:321:24: note: template<class Ch, class A> std::size_t boost::hash_value(const std::basic_string<Ch, std::char_traits<_CharT>, A>&)
/boost/functional/hash/hash.hpp:343:24: note: std::size_t boost::hash_value(std::type_index)
/boost/functional/hash/hash.hpp:343:24: note: no known conversion for argument 1 from ‘const boost::asio::ip::address’ to ‘std::type_index’
/boost/functional/hash/extensions.hpp:54:17: note: template<class A, class B> std::size_t boost::hash_value(const std::pair<_T1, _T2>&)
/boost/functional/hash/extensions.hpp:63:17: note: template<class T, class A> std::size_t boost::hash_value(const std::vector<_Tp, _Alloc>&)
/boost/functional/hash/extensions.hpp:69:17: note: template<class T, class A> std::size_t boost::hash_value(const std::list<_Tp, _Alloc>&)
/boost/functional/hash/extensions.hpp:75:17: note: template<class T, class A> std::size_t boost::hash_value(const std::deque<_Tp, _Alloc>&)
/boost/functional/hash/extensions.hpp:81:17: note: template<class K, class C, class A> std::size_t boost::hash_value(const std::set<_Key, _Compare, _Alloc>&)
/boost/functional/hash/extensions.hpp:87:17: note: template<class K, class C, class A> std::size_t boost::hash_value(const std::multiset<_Key, _Compare, _Alloc>&)
/boost/functional/hash/extensions.hpp:93:17: note: template<class K, class T, class C, class A> std::size_t boost::hash_value(const std::map<_Key, _Tp, _Compare, _Alloc>&)
/boost/functional/hash/extensions.hpp:99:17: note: template<class K, class T, class C, class A> std::size_t boost::hash_value(const std::multimap<_Key, _Tp, _Compare, _Alloc>&)
/boost/functional/hash/extensions.hpp:105:17: note: template<class T> std::size_t boost::hash_value(const std::complex<_Tp>&)
/boost/functional/hash/extensions.hpp:177:9: warning: control reaches end of non-void function [-Wreturn-type]
/boost/asio/error.hpp: At global scope:
/boost/asio/error.hpp:244:45: warning: ‘boost::asio::error::system_category’ defined but not used [-Wunused-variable]
/boost/asio/error.hpp:246:45: warning: ‘boost::asio::error::netdb_category’ defined but not used [-Wunused-variable]
/boost/asio/error.hpp:248:45: warning: ‘boost::asio::error::addrinfo_category’ defined but not used [-Wunused-variable]
/boost/asio/error.hpp:250:45: warning: ‘boost::asio::error::misc_category’ defined but not used [-Wunused-variable]
Here's what I came up with after a brief inspection of the class interface for ip::address.
I would like to note that it's pretty wasteful to use. Especially if you happen to know that all addresses are ipv4, e.g. I'd prefer to key by ulong then.
namespace boost
{
template <>
struct hash<IPAddress>
{
size_t operator()(IPAddress const& v) const {
if (v.is_v4())
return v.to_v4().to_ulong();
if (v.is_v6())
{
auto const& range = v.to_v6().to_bytes();
return hash_range(range.begin(), range.end());
}
if (v.is_unspecified())
{
// guaranteed to be random: chosen by fair dice roll
return static_cast<size_t>(0x4751301174351161ul);
}
return hash_value(v.to_string());
}
};
}
See it Live on Coliru:
#include <boost/asio.hpp>
#include <boost/unordered/unordered_map.hpp>
#include <iostream>
#include <list>
typedef int ApplicationID;
typedef boost::asio::ip::address IPAddress;
typedef std::list<ApplicationID> APP_LIST;
typedef boost::unordered::unordered_map<IPAddress, APP_LIST> USER_MAP;
namespace boost
{
template <>
struct hash<IPAddress>
{
size_t operator()(IPAddress const& v) const {
if (v.is_v4())
return v.to_v4().to_ulong();
if (v.is_v6())
{
auto const& range = v.to_v6().to_bytes();
return hash_range(range.begin(), range.end());
}
if (v.is_unspecified())
return 0x4751301174351161ul;
return hash_value(v.to_string());
}
};
}
int main()
{
USER_MAP map;
map.insert({ {}, {} });
}
This is an old question, but I recently came across the same issue while writing a game in c++17.
This is how I solved it:
struct endpoint_hash
{
std::size_t operator()(boost::asio::ip::udp::endpoint const& ep) const noexcept
{
auto accum = std::size_t(0);
auto combine = [&accum](auto&& arg) {
boost::hash_combine(accum, arg);
};
combine(ep.port());
if (auto&& addr = ep.address(); addr.is_v4())
{
combine(addr.to_v4().to_ulong());
}
else
{
combine(addr.to_v6().to_bytes());
}
combine(ep.port());
return accum;
}
};
std::unordered_map<boost::asio::ip::udp::endpoint, std::shared_ptr<game_client>, endpoint_hash> cache_;
It will work if you write a hash function for IPaddress.
What is the difference between struct reg and struct user_regs_struc on Linux 64 bit machine?
struct user_regs_struct
{
unsigned long r15;
unsigned long r14;
unsigned long r13;
unsigned long r12;
unsigned long rbp;
unsigned long rbx;
unsigned long r11;
unsigned long r10;
unsigned long r9;
unsigned long r8;
unsigned long rax;
unsigned long rcx;
unsigned long rdx;
unsigned long rsi;
unsigned long rdi;
unsigned long orig_rax;
unsigned long rip;
unsigned long cs;
unsigned long eflags;
unsigned long rsp;
unsigned long ss;
unsigned long fs_base;
unsigned long gs_base;
unsigned long ds;
unsigned long es;
unsigned long fs;
unsigned long gs;
};
This struct can be found in /usr/include/x86_64-linux-gnu/sys
According to this link struct reg is
struct reg {
register_t fixreg[32];
register_t lr;
register_t cr;
register_t xer;
register_t ctr;
register_t pc;
};
in freeBsd file: sys/powerpc/include/reg.h
And yes I did not found this struct in my debian 64bit system.