Hello.I have installed the qwt libraries but i don't know how to use them in my qt Creator.I write this on my .pro file but it shows me the following error:
Qt Code: 
  1. INCLUDEPATH+=/usr/local/qwt-5.2/lib
  2.  
  3. LIBS += -lqwt
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error
Qt Code: 
  1. error: collect2: ld returned 1 exit status
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can anyone tell me what do i have to write?All the files are on this path:/usr/loca/qwt-5.2/lib!
Thanks in advance.