[Qt-interest] How can I use gsl in my Qt application?

[Srdjan Todorovic]

Hi,

You did not specify if you have googled and what you have found.

Because we are all friendly here, and because we are your personal
google service ( ;-) ) here's a possible fix for your problem:

http://lucksus.org/2009/02/12/cygwin-and-undefined-reference-to-__getreent/

This may or may not be a proper fix - I suggest you google for
alternative solutions.

Srdjan

On 06/07/2009, ri at eeda.denso.co.jp <ri at eeda.denso.co.jp> wrote:
> Hi.
>
> I use cygwin on Windows to get the libgsl.a  from the source code of gsl.
>
> I found some c++ sample code using gsl:
>
>
> #include <iostream>  // note that .h is omitted
> #include <iomanip>  // note that .h is omitted
> #include <fstream>  // note that .h is omitted
> using namespace std;  // we need this when .h is omitted
>
> #include <gsl/gsl_math.h>
> #include <gsl/gsl_sum.h>
>
> main.cpp
> //*********************************************************************//
> int main (void)
> {
>   // evaluating zeta(2) = \sum_{n=1}^{\infty} 1/n^2
>   const double zeta_2_exact = M_PI * M_PI / 6.0; // exact answer
>
>   const int N = 20;  // up to N terms
>   double t[N];   // array with i'th term
>   double sum = 0;  // accumulated sum
>   for (int n = 0; n < N; n++)
>     {
>       double nplus = n + 1.;
>       t[n] = 1.0 / (nplus * nplus);
>       sum += t[n];
>     }
>
>   double sum_accel, error;
>   gsl_sum_levin_u_workspace *work_ptr = gsl_sum_levin_u_alloc (N);
>   gsl_sum_levin_u_accel (t, N, work_ptr, &sum_accel, &error);
>
>   cout.setf (ios::fixed, ios::floatfield); // output in fixed format
>   cout.precision (18);  // 18 digits in doubles
>
>   const int width = 19;
>   cout << "term-by-term sum = " << setw (width) << sum
>     << " using " << N << " terms" << endl;
>
>   cout << "term-by-term sum = " << setw (width) << work_ptr->sum_plain
>     << " using " << work_ptr->terms_used << " terms" << endl;
>
>   cout << "exact value      = " << setw (width) << zeta_2_exact << endl;
>   cout << "accelerated sum  = " << setw (width) << sum_accel << " using "
>     << work_ptr->terms_used << " terms" << endl;
>
>   cout << "estimated error  = " << setw (width) << error << endl;
>   cout << "actual error     = " << setw (width) << sum_accel - zeta_2_exact
>     << endl;
>
>   gsl_sum_levin_u_free (work_ptr);
>   return 0;
> }
>
> I wrote a pro file using main.cpp as the only source file:
>
> ######################################################################
> # Automatically generated by qmake (2.01a) ? 7 6 18:47:36 2009
> ######################################################################
>
> TEMPLATE = app
> TARGET =
> DEPENDPATH += .
> INCLUDEPATH += C:/work/simpleplot/MyWork/gsl/. .
>
> win32-g++:LIBS   += -lgsl
>
> # Input
> SOURCES += main.cpp
>
>
> but the compiler complains as:
>
> mingw32-make
> c:/Qt/2009.02/qt/bin/qmake.exe -win32 -o Makefile gsl.pro
> mingw32-make -f Makefile.Debug
> mingw32-make[1]: Entering directory `c:/work/simpleplot/MyWork/gsl'
> g++ -enable-stdcall-fixup -Wl,-enable-auto-import
> -Wl,-enable-runtime-pseudo-reloc -mthreads -Wl -Wl,-subsystem,windows -o
> debug/gsl.exe debug/main.o  -L'c:/Qt/2009.02/qt/lib' -lmingw32 -lqtmaind
> -lgsl -lQtGuid4 -lQtCored4
> c:/Qt/2009.02/qt/lib/libgsl.a(error.o)(.text+0x43): In function `gsl_error':
> /cygdrive/c/work/gsl/err/error.c:43: undefined reference to `__getreent'
> c:/Qt/2009.02/qt/lib/libgsl.a(error.o)(.text+0x53):/cygdrive/c/work/gsl/err/error.c:44:
> undefined reference to `__getreent'
> c:/Qt/2009.02/qt/lib/libgsl.a(error.o)(.text+0x7d):/cygdrive/c/work/gsl/err/error.c:45:
> undefined reference to `__getreent'
> c:/Qt/2009.02/qt/lib/libgsl.a(stream.o)(.text+0x82): In function
> `gsl_stream_printf':
> /cygdrive/c/work/gsl/err/stream.c:37: undefined reference to `__getreent'
> c:/Qt/2009.02/qt/lib/libgsl.a(stream.o)(.text+0xd1): In function
> `gsl_set_stream':
> /cygdrive/c/work/gsl/err/stream.c:61: undefined reference to `__getreent'
> collect2: ld returned 1 exit status
> mingw32-make[1]: *** [debug/gsl.exe] Error 1
> mingw32-make[1]: Leaving directory `c:/work/simpleplot/MyWork/gsl'
> mingw32-make: *** [debug] Error 2
>
>
> Can anyone help?
>
>