Reads to EOF on the given file pointer from the current position and writes the results to standard output.
If an error occurs, fpassthru() returns FALSE.
The file pointer must be valid, and must point to a file successfully opened by fopen(), popen(), or fsockopen(). You may need to call rewind() to reset the file pointer to the beginning of the file if you have already written data to the file. The file is closed when fpassthru() is done reading it (leaving fp useless).
Note: When using fpassthru() on a binary file on Windows systems, you should make sure to open the file in binary mode by appending a b to the mode used in the call to fopen().