Where is the string returned by mmap(2) stored?

Question

C++ / C#

And is it necessary to free the memory at this pointer using free()?

char *ptr = mmap(NULL, fileLength, PROT_READ, MAP_PRIVATE, input, 0);

Answer 1

Why not read the documentation.
man7.org/linux/man-pages/man2/mmap.2.html
1) mmap does not return a string. It returns a pointer to the beginning of the mapped area (void*).
2) It is not necessary to release the area, it will be freed when the process is completed. But if you want, there is unmap.
3) It is strictly forbidden to call free on something not allocated by malloc.