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WFDB_wfdbgetstart

Usage: PLENGTH = WFDB_wfdbgetstart(SIG_NUM);  
Input: SIG_NUM: signal number (note: the first signal is signal number 0, etc.)  
Output: PLENGTH: prolog length, in bytes  

This function gets the number of bytes in the prolog of the signal file that contains the specified input signal, as recorded in the header file. Note that WFDB_wfdbgetstart does not determine the length of the prolog by inspection of the signal file; it merely reports what has been determined by other means and recorded in the '.hea' file. Since the prolog is not readable using the WFDB library, and since functions such as WFDB_isigopen and WFDB_isigsettime take the prolog into account when calculating byte offsets for WFDB_getframe and WFDB_getvec, WFDB_wfdbgetstart is useful primarily for programs that need to rewrite existing '.hea' files, where it is necessary to preserve the previously recorded byte offsets.



George B. Moody 2005-06-02