/in/foo.cc:3:1: error: '__int64' does not name a type
 __int64 x,y,n,m,l;
 ^~~~~~~
/in/foo.cc:4:1: error: '__int64' does not name a type
 __int64 gcd(__int64 a,__int64 b)
 ^~~~~~~
/in/foo.cc:8:12: error: variable or field 'exgcd' declared void
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
            ^~~~~~~
/in/foo.cc:8:12: error: '__int64' was not declared in this scope
/in/foo.cc:8:22: error: '__int64' was not declared in this scope
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
                      ^~~~~~~
/in/foo.cc:8:32: error: '__int64' was not declared in this scope
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
                                ^~~~~~~
/in/foo.cc:8:41: error: 'xx' was not declared in this scope
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
                                         ^~
/in/foo.cc:8:44: error: '__int64' was not declared in this scope
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
                                            ^~~~~~~
/in/foo.cc:8:53: error: 'yy' was not declared in this scope
 void exgcd(__int64 a,__int64 b,__int64 &xx,__int64 &yy)
                                                     ^~