View Compilation Error

0_0_23347966_14951.cpp: In function 'void output()':
0_0_23347966_14951.cpp:146:49: error: invalid conversion from 'int (*)(const packetT*, const packetT*)' to 'int (*)(const void*, const void*)' [-fpermissive]
   qsort(packet,packetnum,sizeof(packetT),compare);
                                                 ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/assert.h:17:0,
                 from 0_0_23347966_14951.cpp:2:
GCC4.9.2/x86_64-w64-mingw32/include/stdlib.h:353:16: note: initializing argument 4 of 'void qsort(void*, size_t, size_t, int (*)(const void*, const void*))'
   void __cdecl qsort(void *_Base,size_t _NumOfElements,size_t _SizeOfElements,int (__cdecl *_PtFuncCompare)(const void *,const void *));
                ^