How to load library on linux dynamically?

[zhehongwang]

Hello, everyone.
I have written a library named libtest.so on kubuntu 8.10 with qt 4.4.3.
Here is its code:

extern "C" int sum(int a, int b)
{
  return (a+b);
}

extern "C" int sum(int a, int b)
{
  return (a+b);
}

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I also wrote a function to load it dynamically (the libtest.so is under the same directory):

QLibrary mylib("./libtest");
if (mylib.isLoaded())
  // message 1
else 
  // message 2

QLibrary mylib("./libtest");
if (mylib.isLoaded())
  // message 1
else 
  // message 2

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The result is that the library cannot be loaded, as the message 2 is always shown.

Any suggestion?

Thank you!