View Compilation Error

0_0_39199142_18023.cpp: In function 'int main()':
0_0_39199142_18023.cpp:25:44: error: 'strlen' was not declared in this scope
   25 |         wchar_t *wstr = (wchar_t *)malloc((strlen(buffer) + 1) * sizeof(wchar_t));
      |                                            ^~~~~~
0_0_39199142_18023.cpp:5:1: note: 'strlen' is defined in header '<cstring>'; did you forget to '#include <cstring>'?
    4 | #include <wctype.h>
  +++ |+#include <cstring>
    5 |