Embedded Sound Files.

By using the open SNDFILE with a file descriptor function:

      SNDFILE*  sf_open_fd (int fd, int mode, SF_INFO *sfinfo, int close_desc) ;

it is possible to open sound files embedded within larger files. There are however a couple of caveats:

• Read/Write mode (SFM_RDWR) is not supported.
• Writing of embedded files is only supported at the end of the file.
• Reading of embedded files is only supported at file offsets greater than zero.
• Not all file formats are supported (currently only WAV, AIFF and AU).

The test program multi_file.c in the tests/ directory of the source code tarball shows how this functionality is used to read and write embedded files.