View Compilation Error

0_0_32398539_32368.cpp: In function 'int main()':
0_0_32398539_32368.cpp:17:36: error: invalid conversion from 'int (*)(const int*, const int*)' to 'int (*)(const void*, const void*)' [-fpermissive]
           qsort(a,n,sizeof(int),cmp);
                                    ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/assert.h:17:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/cassert:43,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:33,
                 from 0_0_32398539_32368.cpp:1:
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 *));
                ^