使用SWIG无法将QString从c ++函数返回到PERL函数

Question

I have c++ code (Includes Qt also), i want to call those functions by using Perl. Which we can do by using SWIG, so I have implemented interfaces and did all the stuff need to use them in Perl script.

I have a function in c++ which returns a QString value,

QString get_string()
{
  return QString("mystring");
}

I have written one more class which will be used in perl script where i have a function which calls this get_string() function and returns const char*.

const char* get_const_string()
{
   QString str = get_string();

 **//here I print str and str .toLocal8Bit().constData()
 //both are printing the text which i shoud get here**

   return str.toLocal8Bit().constData();

   //here I have tried diff combinations also, as 
   // return str.toStdString().c_str();
}

The problem is, in get_const_string() function, I could get the string I wanted, but when I call this function in my perl script, I am getting undefine value ie null string

.

Any idea, what is the problem here ??

I am using perl5, Qt4.8.4

Thanks in advance.

Answer 1

if you cant use a QString return value, maybe you can use std::string .

if both fail and you do not have limitations, you could do some dirty trick:

QString get_string()
{
  static QByteArray arr;
  QString str = getString();
  arr = str.toLocal8Bit();
  return arr.constData();
}

note that the arr variable will not be free'd untill your app is running

edit: found a possible solution to just use std::string ... string arguments are not recognized by SWIG