AFsetHinfo(3tsp)

Routine
void AFsetHinfo (const char Info[])
char *AFgetHinfo (void)

Purpose
Set the audio file header information string
Get the audio file header information string

Description
This routine sets the information string to be written to an audio file header. By default the header information records specify the date and user name. This routine allows the user to specify information records that are used in addition to, or in place of, the standard header information. This routine must be called before the audio file to be created is first opened using AFopenWrite. AFopenWrite resets the header string to a NULL string.

Standard Header Information:
  date: 1994-01-25 19:19:39 UTC    date
  sample_rate: 8012.5              sampling frequency (if non-integer)
  user: kabal@aldebaran            user
  program: CopyAudio               program name (set by UTsetProg)

Additional structured information records should follow this format; a named field terminated by a colon followed by numeric data or a character string. Comments can follow as unstructured information.
  Record delimiter: Newline character or the two character escape
      sequence "\" + "n".  The last record need not have a delimiter.
  Line delimiter: Within records, lines are delimiteded by a carriage
      control character, the two character escape sequence "\" + "r",
      or the two character sequence "\" + newline.
If the information string starts with a record delimiter, the header information string is appended to the standard header information. If not, the user supplied header information string appears alone.

If the input header information string is a NULL pointer, the standard information is used. If the header information string starts with a record delimiter, the input header information string is added to the existing information records (the standard information and/or any previously specified records). Otherwise the input header information string replaces the standard information. The following examples illustrate the behaviour.

- AFsetHinfo (NULL)
Reset, use only the standard information records
- AFsetHinfo ("")
No header information records
- AFsetHinfo ("<info>")
Replace existing information with <info>; do not use the standard information records
- AFsetHinfo ("\n<info>")
Add <info> to the existing information string.

The procedure AFgetHinfo is used internally by the audio file routines to retrieve the user supplied header information string.

Parameters
AFsetHinfo:
 -> const char Info[]
String containing the user supplied header information
AFgetHinfo:
<- char *AFgetUinfo
Pointer to the header information string. A NULL pointer indicates that no information string has been set.

Author / revision
P. Kabal Copyright (C) 2000 / Revision 1.36 2000/11/21

See Also
AFopenWrite, AFsp