I have declared a function in the c++ file as stated in the documentation and called it in the .ned file. But it gives the following error.
error:expected constructor, destructor, or type conversion before ‘(’ token Define_Function(dijkstra, 1);
The following is my c++ file.
#include <omnetpp.h>
#include "stdio.h"
#include "Node.h"
#include "cdelaychannel.h"
Define_Function(dijkstra, 1);
double dijkstra(double start = 1){
....
....
}
In my network description file, I've called the function.
package myproject;
#license(LGPL);
dijkstra(1.0);
Why is it giving me the error?
If you want to create a function for using it in NED files, you have to do it as described in OMNeT++ Manual. An example could be the following:
static cNEDValue ned_foo(cComponent *context, cNEDValue argv[], int argc)
int a = (long) argv[0];
int b = (long) argv[1];
return a*b;
}
Define_NED_Function(ned_foo,"int ned_foo(int a, int b)");
Related
l learned "include" keyword are just copy & paste.
But including cpp file makes different compile result.
(gcc6~8 + boost1.69)
// main.cpp
#include <iostream>
// I'll move next code to why.cpp
#include <boost/archive/iterators/base64_from_binary.hpp>
#include <boost/archive/iterators/binary_from_base64.hpp>
#include <boost/archive/iterators/transform_width.hpp>
#include <boost/archive/iterators/insert_linebreaks.hpp>
#include <boost/archive/iterators/remove_whitespace.hpp>
void testFunc()
{
using namespace boost::archive::iterators;
typedef transform_width<binary_from_base64<remove_whitespace<std::string::const_iterator>>, 8, 6> ItBinaryT;
std::string input;
std::string output(ItBinaryT(input.begin()), ItBinaryT(input.end()));
}
// -----------------------------
int main()
{
return 0;
}
Above code compiled without warning.
But, I replace some code with include cpp..
// main.cpp
#include <iostream>
#include "why.cpp" // <----------
int main()
{
return 0;
}
// why.cpp - just copy&paste
#include <boost/archive/iterators/base64_from_binary.hpp>
#include <boost/archive/iterators/binary_from_base64.hpp>
#include <boost/archive/iterators/transform_width.hpp>
#include <boost/archive/iterators/insert_linebreaks.hpp>
#include <boost/archive/iterators/remove_whitespace.hpp>
void testFunc()
{
using namespace boost::archive::iterators;
typedef transform_width<binary_from_base64<remove_whitespace<std::string::const_iterator>>, 8, 6> ItBinaryT;
std::string input;
std::string output(ItBinaryT(input.begin()), ItBinaryT(input.end()));
}
It makes warning [-Wsubobject-linkage]
~~ has a field ~~ whose type uses the anonymous namespace
~~ has a base ~~ whose type uses the anonymous namespace
Please look at this link : https://wandbox.org/permlink/bw53IK2ZZP5UWMGk
What makes this difference?
Your compiler treats the main CPP file specially under the assumption that things defined in it are very unlikely to have more than one definition and so some tests for possible violation of the One Definition Rule are not done inside that file. Using #include takes you outside that file.
I would suggest just not using -Wsubobject-linkage since its logic is based on a heuristic that is not applicable to your code.
Here is the minimal C program to reproduce:
#include <alsa/asoundlib.h>
#include <sys/time.h>
int main( void )
{
}
This will compile with gcc -c -o timealsa.o timealsa.c, but if you include the -std=c99 switch, you get a redefinition error:
In file included from /usr/include/sys/time.h:28:0,
from timealsa.c:3:
/usr/include/bits/time.h:30:8: error: redefinition of ‘struct timeval’
struct timeval
^
In file included from /usr/include/alsa/asoundlib.h:49:0,
from timealsa.c:2:
/usr/include/alsa/global.h:138:8: note: originally defined here
struct timeval {
^
How can I resolve this conflict while still using -std=c99?
Since your question suggests you are using GLIBC's time.h there is a way to avoid this by telling it not to define timeval. Include asoundlib.h first then define _STRUCT_TIMEVAL. The one defined in asoundlib.h will be the one that gets used.
#include <alsa/asoundlib.h>
#ifndef _STRUCT_TIMEVAL
# define _STRUCT_TIMEVAL
#endif
#include <sys/time.h>
int main( void )
{
}
With C99 and later you can't have duplicate definitions of the same struct. The problem is that alsa/asoundlib.h includes alsa/global.h which contains this code:
/* for timeval and timespec */
#include <time.h>
...
#ifdef __GLIBC__
#if !defined(_POSIX_C_SOURCE) && !defined(_POSIX_SOURCE)
struct timeval {
time_t tv_sec; /* seconds */
long tv_usec; /* microseconds */
};
struct timespec {
time_t tv_sec; /* seconds */
long tv_nsec; /* nanoseconds */
};
#endif
#endif
So the Michael Petch's solution won't work - by the time you've included alsa/asoundlib.h it is already too late. The proper solution is to define _POSIX_C_SOURCE (_POSIX_SOURCE is obsolete). There's more information about these macros here and here.
For example you could try -D_POSIX_C_SOURCE=200809L. However, if you do that you'll get errors like this:
/usr/include/arm-linux-gnueabihf/sys/time.h:110:20: error: field ‘it_interval’ has incomplete type
struct timeval it_interval;
^
/usr/include/arm-linux-gnueabihf/sys/time.h:112:20: error: field ‘it_value’ has incomplete type
struct timeval it_value;
^
/usr/include/arm-linux-gnueabihf/sys/time.h:138:61: error: array type has incomplete element type
extern int utimes (const char *__file, const struct timeval __tvp[2])
^
This is all a big mess of old C code and macro madness. The only way I got it to work was to give up and use -std=gnu11.
I'm having trouble with std::initializer_list. I reduced it down to a simple example:
#include <initializer_list>
#include <cstdio>
class Test {
public:
template <typename type> Test(const std::initializer_list<type>& args) {}
};
int main(int argc, char* argv[]) {
Test({1,2});
getchar();
return 0;
}
When compiled using g++ test_initializer.cpp -std=c++0x, it compiles and runs well. However, if line 11 is changed to Test({1,2.0});, one gets:
ian#<host>:~/Desktop$ g++ test_initializer.cpp -std=c++0x
test_initializer.cpp: In function ‘int main(int, char**)’:
test_initializer.cpp:11:14: error: no matching function for call to ‘Test::Test(<brace-enclosed initializer list>)’
test_initializer.cpp:11:14: note: candidates are:
test_initializer.cpp:7:28: note: template<class type> Test::Test(const std::initializer_list<_Tp>&)
test_initializer.cpp:5:7: note: constexpr Test::Test(const Test&)
test_initializer.cpp:5:7: note: no known conversion for argument 1 from ‘<brace-enclosed initializer list>’ to ‘const Test&’
test_initializer.cpp:5:7: note: constexpr Test::Test(Test&&)
test_initializer.cpp:5:7: note: no known conversion for argument 1 from ‘<brace-enclosed initializer list>’ to ‘Test&&’
I suspect this happens because the compiler can't figure out what type to make the initializer list. Is there a way to fix the example so that it works with different types (and still uses initializer lists)?
An std::initializer_list takes only one type. If you need different types, you can use variadic templates:
template<typename... Args>
Test(Args&&... args);
/* ... */
int main()
{
Test(1, 2.0);
}
Would a std::tuple<int.double> work for the OP? If the code will always have a int followed by a double, then the OP could get strict type-checking for all arguments, which the variable arguments solution does not allow. The std::tuple<>, however, would not work for any number or order of values, so may not be appropriate for all use cases.
Let the initializer_list hold the most arbitrary pointers, void*, and do your own casting from there. Here is an example.
#include <initializer_list>
#include <iostream>
using std::initializer_list;
using std::cout;
using std::endl;
class Person {
private:
string _name;
int _age;
public:
Person(initializer_list<void*> init_list) {
auto it = init_list.begin();
_name = *((string*)(*it));
it++;
_age = *((int*)(*it));
}
void print() {
cout << "name: " << _name << ". age: " << _age << endl;
}
};
int main(void) {
string name{"Vanderbutenburg};
int age{23};
Person p{&name,&age};
p.print(); // "name: Vanderbutenburg. age: 23"
return 0;
}
I am trying to convert a c++ program I have which uses random library which is a C++11 feature. After having read through a couple of similar posts here, I tried by separating out the code into three files. At the outset I would like to say that I am not very conversant at C/C++ and mostly use R at work.
The main file looks as follows.
#ifndef _KERNEL_SUPPORT_
#define _KERNEL_SUPPORT_
#include <complex>
#include <random>
#include <iostream>
#include "my_code_header.h"
using namespace std;
std::default_random_engine generator;
std::normal_distribution<double> distribution(0.0,1.0);
const int rand_mat_length = 24561;
double rand_mat[rand_mat_length];// = {0};
void create_std_norm(){
for(int i = 0 ; i < rand_mat_length ; i++)
::rand_mat[i] = distribution(generator);
}
.
.
.
int main(void)
{
...
...
call_global();
return 0;
}
#endif
The header file looks as follows.
#ifndef mykernel_h
#define mykernel_h
void call_global();
void two_d_example(double *a, double *b, double *my_result, size_t length, size_t width);
#endif
And the .cu file looks like the following.
#ifndef _MY_KERNEL_
#define _MY_KERNEL_
#include <iostream>
#include "my_code_header.h"
#define TILE_WIDTH 8
using namespace std;
__global__ void two_d_example(double *a, double *b, double *my_result, size_t length, size_t width)
{
unsigned int row = blockIdx.y*blockDim.y + threadIdx.y;
unsigned int col = blockIdx.x*blockDim.x + threadIdx.x;
if ((row>length) || (col>width)) {
return;
}
...
}
void call_global()
{
const size_t imageLength = 528;
const size_t imageWidth = 528;
const dim3 threadsPerBlock(TILE_WIDTH,TILE_WIDTH);
const dim3 numBlocks(((imageLength) / threadsPerBlock.x), ((imageWidth) / threadsPerBlock.y));
double *d_a, *d_b, *mys ;
...
cudaMalloc((void**)&d_a, sizeof(double) * imageLength);
cudaMalloc((void**)&d_b, sizeof(double) * imageWidth);
cudaMalloc((void**)&mys, sizeof(double) * imageLength * imageWidth);
two_d_example<<<numBlocks,threadsPerBlock>>>(d_a, d_b, mys, imageLength, imageWidth);
...
cudaFree(d_a);
cudaFree(d_b);
}
#endif
Please note that the __global__ has been removed from .h since I was getting the following error owing to it being compiled by g++.
In file included from my_code_main.cpp:12:0:
my_code_header.h:5:1: error: ‘__global__’ does not name a type
When I compile the .cu file with nvcc it is all fine and generates a my_code_kernel.o. But since I am using C++11 in my .cpp I am trying to compile it with g++ and I am getting the following error.
/tmp/ccR2rXzf.o: In function `main':
my_code_main.cpp:(.text+0x1c4): undefined reference to `call_global()'
collect2: ld returned 1 exit status
I understand that this might not have to do anything with CUDA as such and may just be the wrong use of including the header at both places. Also what is the right way to compile and most importantly link the my_code_kernel.o and my_code_main.o(hopefully)? Sorry if this question is too trivial!
It looks like you are not linking with my_code_kernel.o. You have used -c for your nvcc command (causes it to compile but not link, i.e. generate the .o file), I'm going to guess that you're not using -c with your g++ command, in which case you need to add my_code_kernel.o to the list of inputs as well as the .cpp file.
The separation you are trying to achieve is completely possible, it just looks like your not linking properly. If you still have problems, add the compilation commands to your question.
FYI: You don't need to declare two_d_example() in your header file, it is only used within your .cu file (from call_global()).
I am working on a project where I need to change the behaviour of the XOpenDisplay function defined in X11/Xlib.h.
I have found an example, which should do exactly what I am looking for, but when I compile it, I get the following error messages:
XOpenDisplay_interpose.c:14: Error: conflicting types for »XOpenDisplay«
/usr/include/X11/Xlib.h:1507: Error: previous declaration of »XOpenDisplay« was here
Can anyone help me with that problem? What am I missing?
My program code so far - based on the example mentioned above:
#include <stdio.h>
#include <X11/Xlib.h>
#include <dlfcn.h>
Display *XOpenDisplay(char *display_name)
{
static Display *(*func)(char *);
Display *ret;
void* handle=NULL;
handle = dlopen ("XOpenDisplay_interpose.so", RTLD_LAZY);
if(!handle){
fprintf(stderr, "ERROR dlopen\n");
}
if(!func)
func = (Display *(*)(char *))dlsym(handle,"XOpenDisplay");
if(display_name)
printf("XOpenDisplay() is called with display_name=%s\n", display_name);
else
printf("XOpenDisplay() is called with display_name=NULL\n");
ret = func(display_name);
printf(" calling XOpenDisplay(NULL)\n");
ret = func(0);
printf("XOpenDisplay() returned %p\n", ret);
return(ret);
}
int XCloseDisplay(Display *display_name)
{
static int (*func)(Display *);
int ret;
void* handle=NULL;
handle = dlopen ("XOpenDisplay_interpose.so", RTLD_LAZY);
if(!handle){
fprintf(stderr, "ERROR dlopen\n");
}
if(!func)
func = (int (*)(Display *))dlsym(handle,"XCloseDisplay");
ret = (int)func(display_name);
printf("called XCloseDisplay(%p)\n", display_name);
return(ret);
}
int main()
{
}
Regards,
Andy.
The declaration reads like this:
Display *XOpenDisplay(_Xconst char *display_name)
So just adding a 'const' should suffice.