I am new to C++ and I am using Eclipse to write a script. My OS is Ubuntu. I need to use the LAPACKE package partially for my code. I however cannot manage to link Eclipse and LAPACKE. I am trying to compile the following sample code:
#include <stdio.h>
#include <lapacke.h>
int main (int argc, const char * argv[])
{
double a[5][3] = {1,1,1,2,3,4,3,5,2,4,2,5,5,4,3};
double b[5][2] = {-10,-3,12,14,14,12,16,16,18,16};
lapack_int info,m,n,lda,ldb,nrhs;
int i,j;
m = 5;
n = 3;
nrhs = 2;
lda = 3;
ldb = 2;
info = LAPACKE_dgels(LAPACK_ROW_MAJOR,'N',m,n,nrhs,*a,lda,*b,ldb);
for(i=0;i<n;i++)
{
for(j=0;j<nrhs;j++)
{
printf("%lf ",b[i][j]);
}
printf("\n");
}
return(info);
}
I am unable to compile the code as my Eclipse throws the error: "Udefined reference to LAPACKE_dgels". I have tried to link Eclipse to LAPACKE, for which I have added the path to LAPACKE header files in the "Paths and Symbols" tab of Eclipse. Can anyone help with what I need to do in order to resolve this issue? I should be missing something ...
I assume you are using gcc compiler. I guess you are missing -llapack flag in the compile arguments. If it doesn't work, try -llapacke. This flag (-l[LibraryName]) tells linker to use external binaries (see: gcc: Difference between -L and -l option AND how to provide complete path to a library).
Check out this question to see how to add compiler flags in Eclipse: How to add compiler options in Eclipse IDE
Related
I write a simple c++ program that use new function and don't use delete function, then I use asan, but it not report.
#include <iostream>
#include <stdint.h>
using namespace std;
int main()
{
int *p = new int[50];
for (uint32_t i = 0; i < 50; ++i)
{
*(p + i ) = i;
}
cout << *p << endl;
return 0;
}
then ./g++ main.cpp -lasan -L/root/local/lib64/ -fsanitize=address -fno-omit-frame-pointer -g
and print 0, but not report delete leak . why ?
if I use export LD_PRELOAD=/usr/local/lib64/libasan.so.0.0.0, then ./g++ main.cpp
report
g++: internal compiler error: Segmentation fault (program collect2)
0x40c400 execute
../../gcc/gcc.c:2823
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
it look like collect2 core dump ,so I run cd libexec/gcc/x86_64-unknown-linux-gnu/4.8.5/ && ./colloct2, report Segmentation fault (core dumped)
I use source to install gcc-4.8.5, centos 6.
gcc-4_8-branch doesn't even contain libsanitizer/lsan/ directory. Please try more recent GCC versions. by https://github.com/google/sanitizers/issues/699
Why does the value of strings in Eclipse Mars CDT not appear in the expression or variables windows?
It appears {...} but i want to see the value itself under the value tab.
How can i do this?
What is going on here is CDT is showing the information that GDB is providing to it.
For a trivial program, with the debugger stopped on the line with return 0;
#include <string>
using namespace std;
int main() {
string mystring = "my string here";
return 0;
}
this is what I see in the CDT variable view:
which matches what I see in GDB:
(gdb) p mystring
$1 = {static npos = <optimised out>,
_M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>},
_M_p = 0x602028 "my string here"}}
Pretty Printing C++
However, what I suspect you want is the pretty printers for libstdc++ which makes the variables view look like this:
Create a ~/.gdbinit file with the following contents (updating the path for your machine)
python
import sys
sys.path.insert(0, '/usr/share/gcc-4.8/python/')
from libstdcxx.v6.printers import register_libstdcxx_printers
register_libstdcxx_printers (None)
end
Then point your launch configuration at that gdbinit file and start debugging.
GDB wiki entry on the subject:
https://sourceware.org/gdb/wiki/STLSupport
GCC manual entry:
https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug.html
I am using Eclipse Juno updated as two days ago, fresh install and installed C/C++ and linked MinGW into Windows (7 64-bit by the way). Everything works fine, i can build/compile "Hello World" and execute the file generated by eclipse.
Now i have three files,
main.cpp:
#include "functions.cpp"
#include <iostream>
using namespace std;
int main(int){
int a = mult(20,5);
cout << "Twenty times 5 is " << a;
cout << a << "Plus 2 is " << add2(a);
return 0;
}
functions.cpp:
#include "header.h"
int EXPORT add2(int num){
return num + 2;
}
int EXPORT mult(int num1, int num2){
int product;
product = num1 * num2;
return product;
}
header.h:
#ifndef HEADER_H_
#define HEADER_H_
#ifdef BUILD_DLL
#define EXPORT __declspec(dllexport)
#else
#define EXPORT __declspec(dllimport)
#endif
int EXPORT add2(int num);
int EXPORT mult(int num1, int num2);
#endif /* HEADER_H_ */
With this set up in the code i need a DLL file to be generated first and then used when building. If i place these files on my desktop for instance, i can /cd desktop and use this command:
g++ functions.cpp -o functions.dll -DBUILD_DLL -shared -Wl,--out-implib,libfunctions.dll.a
This creates a DLL file and also a .A File, one dynamic one static.
IN SHORT MY QUESTION:
Can i get Eclipse to make a DLL file from functions.cpp before it attempts to build my code into a .exe file? At this stage my code is looking for an DLL file to IMPORT.
I found out how to do this. It may not be the best option for this, however i was able to go to my project Properties-->C/C++ Build--->Settings--->Build Steps.
This seems to work however I am now trying to find a way to set the command to use the source directory of the project instead of me having to use C:/eclipse/workplace etc.
I'm using Eclipse 4.2, with CDT, and MinGW toolchain on a Windows machine (although I've a feeling the problem has nothing to do with this specific configuration). The G++ compiler is 4.7
I'm playing with c++11 features, with the following code:
#include <iostream>
#include <iomanip>
#include <memory>
#include <vector>
#include <list>
#include <algorithm>
using namespace std;
int main( int argc, char* argv[] )
{
vector<int> v { 1, 2, 3, 4, 5, 6, 7 };
int x {5};
auto mark = remove_if( v.begin(), v.end(), [x](int n) { return n<x; } );
v.erase( mark, v.end() );
for( int x : v ) { cout << x << ", "; }
cout << endl;
}
Everything is very straight forward and idiomatic c++11. The code compiles with no problems on the command line (g++ -std=c++11 hello.cpp).
In order to make this code compile In eclipse, I set the compiler to support C++11:
Properties -> C/C++ Build -> Settings -> Miscellaneous -> Ohter Flags:
I'm adding -std=c++11
Properties -> C/C++Build -> Discovery Options -> Compiler invocation arguments:
Adding -std=c++11
That's the only change I did to either the global preferences or to the project properties.
First Question: Why do I've to change the flags in two places? When each compiler flags is used?
If I hit Ctrl-B, the project will build successfully, as expected, and running it from within eclipse show the expected result (It prints: '5, 6, 7,').
However, the editor view shows red marks of error on both the 'remove_if' line, and the 'v.erase' line. Similarly, the Problems view shows I've these two problems. Looking at the details of the problem, I get:
For the remove_if line: 'Invalid arguments. Candidates are: #0 remove_if(#0, #0, #1)
For the erase line: 'Invalid arguments Candidates are: '? erase(?), ? erase(?,?)'
Second questions: It appears there are two different builds: one for continues status, and one for the actual build. Is that right? If so, do they have different rule (compilation flags, include paths, etc.)?
Third question: In the problem details I also see: 'Name resolution problem found by the indexer'. I guess this is why the error message are so cryptic. Are those messages coming from MinGW g++ compiler or from Eclipse? What is this Name resolution? How do I fix?
Appreciate your help.
EDIT (in reply to #Eugene): Thank you Eugene. I've opened a bug on Eclipse. I think that C++11 is only partially to blame. I've cleaned my code from C++11 stuff, and removed the -std=c++11 flag from both compilation switch. And yet, the CodAn barks on the remove_if line:
int pred( int n ) { return n < 5; }
int main( int argc, char* argv[] )
{
vector<int> v;
for( int i=0; i<=7; ++i ) {
v.push_back( i );
}
vector<int>::iterator mark = remove_if( v.begin(), v.end(), pred );
v.erase( mark, v.end() );
for( vector<int>::iterator i = v.begin(); i != v.end(); ++i ) {
cout << *i << ", ";
}
cout << endl;
}
The code compiles just fine (with Ctrl-B), but CodAn doesn't like the remove_if line, saying: Invalid Arguments, Candidates are '#0 remove_if(#0,#0,#1)'.
This is a very cryptic message - it appears it misses to substitute arguments in format string (#0 for 'iterator' and #1 for 'predicate'). I'm going to update the bug.
Interestingly, using 'list' instead of 'vector' clears up the error.
However, as for my question, I'm curious about how the CodAn work. Does it uses g++ (with a customized set of flags), or another external tool (lint?), or does it do it internally in Java? If there is a tool, how can I get its command line argument, and its output?
Build/Settings - these flags will be included into your makefile to do actual build. Build/Discovery - these flags will be passed to a compiler when "scanner settings" are discovered by IDE. IDE will run compiler in a special mode to discover values of the predefined macros, include paths, etc.
I believe, the problems you are seeing are detected by "Codan". Codan is a static analysis built into the CDT editor, you may find its settings on "C/C++ General"/"Code Analysis". You should report the problem to the bugs.eclipse.org if you feel the errors shown are bogus. Note that CDT does not yet support all C++11 features.
i have problem with libhid .
i found that there 2 way 4 accessing the usb-hid in linux
1)linux default libraries like input.h and hiddev.h and ...
2)using libhid
i found libhid some confusing and try to use input.h but i have problem with that 2.
i dont know how to get information about my device from ubuntu
i use open() to open the device
str="/dev/inpt/eventX" \\where X=0,1,...,7(I'm not sure about this)
open(str,O_RDWR)
then get info with ioctl
ioctl(fd,EVIOCGVERSION,&version);
but it give me wrong vendor and product IDs
then
i try to use libhid but had know idea how to use libhid (or any other library) in eclipse or netbeans
can you tell me how you compiled your codes any IDE like eclipse or netbeans or just using terminal and gcc?
or
how to work with ioctl() and open() ?
my whole example code:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ftw.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
#include <stdint.h>
#include <asm/types.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/usbdevice_fs.h>
#include <linux/input.h>
#include <strings.h>
struct input_devinfo
{
uint16_t bustype;
uint16_t vendor;
uint16_t product;
uint16_t version;
};
int main(void) {
//puts("!!!Hello World!!!"); /* prints !!!Hello World!!! */
//usb_device ud;
//int i=0;
//string str;
//str=char[100];
//str="/dev/input/event0\n";
printf("------------- start -----------------\n");
char str[]="" ;
int version=0;
char c[16];
char t;
int i,fd;
//for (i=0 ; i<8 ; i++)
{
//strcpy(c,str);
//t=i-'0';
//printf("salam5\n");
//c[15]=t;
//openning
//open(str,O_RDONLY);//read and write
if ((fd = open(str,O_RDWR)) < 0)
perror("str open\n");
else
printf("%s opened successfully\n",str);
ioctl(fd,EVIOCGVERSION,&version);
printf("version = %d \n",version);
printf("evdev driver version is %d.%d.%d\n",version >> 16, (version >> 8) & 0xff, version & 0xff);
//geting info from device
struct input_devinfo device_info;
ioctl(fd,EVIOCGID,&device_info);
printf("vendor 0x%04hx product 0x%04hx version 0x%04hx is on ?",
device_info.vendor, device_info.product,
device_info.version);
}
return EXIT_SUCCESS;
}
I find a way to compile my code in eclipse
1 problem solved
to compile your code with GCC in terminal you should define libhid for GCC by adding "-lhid" to your command :
gcc test_libhid.c -lhid
if your using eclipse and you want to use libhid with it you should add "-lhid" to gcc linker in order to gcc could use libhid when its compiling your code
follow the steps:
1)on the project Explorer panel , R-click on your project select properties (last option)
or select your project and press Alt+Enter
2)in the left panel expand "c/c++ build" and select "setting"
3)in the right side select "tool setting" tab
4)you should see GCC C compiler and GCC C linker and GCC assembler in there .
expand GCC C linker and select Libraries
5)after selecting in the right side you should see 2 boxes: Libraries(-l) and Library search path(-L)
in the Libraries(-l) add "hid"
note:eclipse use GCC to compile your codes when you do this steps eclipse add "-lhid" parameter to gcc to able it recognizing the libhid.