pointer to template function when using qsort

Question

0.00/5 (No votes)

See more:

Hi
i what to use the QSort function and one of it's arguments is the pointer of the sort function, the problem is when i calling the template sort function

The sort function:

C++

template <class VAL_TYPE> int sortFunction2(const void *arg1,const void *arg2)
{
    VAL_TYPE d1 = (VAL_TYPE) arg1;
    VAL_TYPE d2 = (VAL_TYPE) arg2;

    if(*d1>*d2) return 1;
    if(*d1<*d2) return -1;
    return 0;


}

when using this function when using long double every thing ok

C++

int sortFunction1(const void *arg1,const void *arg2)
{
    long double *d1 = (long double *) arg1;
    long double *d2 = (long double *) arg2;

    if(*d1>*d2) return 1;
    if(*d1<*d2) return -1;
    return 0;


}

when using:
qsort(ResultNorm_Ref,32,sizeof(long double),sortFunction1);

but when using:
qsort(ResultNorm_Ref,32,sizeof(long double),sortFunction2<long double>);
i getting this error :

VB

error C2664: 'qsort' : cannot convert parameter 4 from 'int (const void *,const void *)' to 'int (__cdecl *)(const void *,const void *)'
        None of the functions with this name in scope match the target type

and when using this:
qsort(ResultNorm_Ref,32,sizeof(long double),<long double>sortFunction2);

i getting this error: error C2059: syntax error : '<'

how can i call the template sort function using the qsort function?

Thanks

Posted 10-Apr-10 22:32pm

pascal.schwartz

Updated 10-Apr-10 23:13pm

Saurabh.Garg

v3

Add a Solution

3 solutions

Solution 1

Which compiler are you using? Following code works with VS 2008.

C++

#include <cstdlib>

template <class VAL_TYPE>
int sortFunction2(const void *arg1,const void *arg2)
{
    VAL_TYPE* d1 = (VAL_TYPE*)arg1;
    VAL_TYPE* d2 = (VAL_TYPE*)arg2;
    if(*d1>*d2) return 1;
    if(*d1<*d2) return -1;
    return 0;
}

int main(int argc, char* argv[])
{
    long double x[8] = {10, 9, 8, 7, 6, 5, 4, 3};
    qsort(x, 8, sizeof(long double), sortFunction2<long double>);
    return 0;
}

-Saurabh

Posted 10-Apr-10 23:14pm

Saurabh.Garg

Solution 2

Hi Thanks for the reply i tried it but i am still getting error:

'qsort' : cannot convert parameter 4 from 'int (const void *,const void *)' to 'int (__cdecl *)(const void *,const void *)'

1. I am using the vs2005 in MFC project the qsort is under stdlib.h.
2. could it be something with the

(__cdecl *)

? what it does any way?

Thanks

Posted 11-Apr-10 22:34pm

pascal.schwartz

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Saurabh.Garg · Accepted Answer · 2010-04-11T22:54:00

Solution 3

I don't have VS 2005 but cPallini tested this code on VS2005 and it works fine for him. Can you check that Calling Conventions under Project -> Properties -> Configuration Properties -> C/C++ -> Advanced is set to _cdecl(/Gd).

-Saurabh

Posted 11-Apr-10 22:54pm

Saurabh.Garg