int unlink(const char *pathname);
On success, zero is returned. On error, -1 is returned.
No access to the file or the path of the file.
The system does not allow unlinking of directories.
The file pathname cannot be unlinked because it’s being used by another process.
pathnameptr is an invalid pointer value.
pathname was too long.
A directory component in pathname does not exist.
A component of the path is not a directory.
The file is on a read-only filesystem.
The call was interrupted by the user.