Hi there. While compiling a file I keep on receiving two warnings and one error -
D:\Spatial sources\projects\QUnwrap/qunwrap.cpp:14: undefined reference to `start_unwrap(int, char**)'
D:\Spatial sources\projects\QUnwrap/qunwrap.cpp:14: undefined reference to `start_unwrap(int, char**)'
error: collect2: ld returned 1 exit status

Qt Code: 
  1. #include "qunwrap.h"
  2. #include "ui_qunwrap.h"
  3.  
  4. #include "snaphu_src/snaphu.h"
  5.  
  6. QUnwrap::QUnwrap(QWidget *parent) :
  7.     QMainWindow(parent),
  8.     ui(new Ui::QUnwrap)
  9. {
  10.     ui->setupUi(this);
  11.  
  12.     int first_arg;
  13.     char** sec_arg;
  14.     start_unwrap(first_arg, sec_arg);
  15. }
  16.  
  17. QUnwrap::~QUnwrap()
  18. {
  19.     delete ui;
  20. }
  21.  
  22. void QUnwrap::changeEvent(QEvent *e)
  23. {
  24.     QMainWindow::changeEvent(e);
  25.     switch (e->type()) {
  26.     case QEvent::LanguageChange:
  27.         ui->retranslateUi(this);
  28.         break;
  29.     default:
  30.         break;
  31.     }
  32. }
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File "snaphu.h"

Qt Code: 
  1. .....
  2. void start_unwrap(int argc, char **argv);// main procedure
  3. .....
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File "snaphu.c"
Qt Code: 
  1. void start_unwrap(int argc, char **argv){
  2. //some code here
  3. }
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If I comment the line
Qt Code: 
  1. start_unwrap(first_arg, sec_arg);
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, Qt compiles it.
What's wrong with it? I'm using QT Creator. Thank you for any help in advance.