WFDB 10.7

New features in version 10.7

The WFDB library now supports storing signals in compressed form, using the FLAC (Free Lossless Audio Codec) algorithm. Compressed signal files are designated by the the format code 508, 516, or 524 (depending on the signal resolution.) In order to read and write signals in these formats, the FLAC library and header files must be installed when compiling the WFDB Software Package.

If the symbol WFDB_LARGETIME is defined before including wfdb.h, then the type WFDB_Time is defined as a long long rather than a long (see section Large Time Values).

New macros, defined in ‘wfdb.h’, can be used to construct format strings for printf() (see section Displaying Numeric Values) and scanf() (see section Parsing Numeric Values), independent of the underlying data types.

If high-resolution mode is enabled using setgvmode(), then sampfreq(r) will return the highest sampling frequency of any signal in record r, and subsequent calls to mstimstr() and strtim() will likewise interpret sample and frame numbers just as if the record were actually opened using isigopen().

If an error occurs while writing an output file, the library usually cannot detect the error until the file is closed. (For example, after calling putvec(), the output samples will be buffered, but there might not be enough disk space to store them.) In order to check that the output was written successfully, an application can call ‘osigfopen(NULL, 0)’ (for signal and header files), ‘annopen("", NULL, 0)’ (for annotation files), or ‘setinfo(NULL)’ (for info files). These function calls also work with previous versions of the library, but would always return 0.

In calibration files, the signal description ‘*’ is treated as a wildcard entry that will match any signal with the specified units.

When reading a multi-frequency record using getvec() or sample(), the resampled values will be correctly rounded to the nearest integer, and will be calculated correctly for large numbers of samples per frame.

The Fortran wrapper functions have improved support for working with “native Fortran” string data (when FIXSTRINGS is defined), allowing Fortran programs to work with strings containing embedded spaces. These functions will now avoid buffer overflows, both with and without FIXSTRINGS.

The macros SALLOC, SUALLOC, SREALLOC, SSTRCPY, and MEMERR will avoid evaluating their arguments more than once (except for the pointer argument.) These macros will now handle zero-byte allocations consistently, and will check for integer overflows.

osigopen() permits the siarray argument to be NULL (like isigopen().)

Bugs fixed in version 10.7.0 (10 June 2022)

A number of corner cases have been fixed in getframe(). It now correctly handles skewed signals in variable-layout records, records with multiple signal files, and records with signal file prologs. It also correctly handles multi-segment records with signal file prologs, and multi-segment records where some signal files are missing. The wfdbgetskew() and wfdbsetiskew() functions now work as documented.

Functions for reading header, calibration, and info files will now correctly handle lines of any length, rather than being limited to 255 or 126 characters per line.

In the WFDB path, colons can be used within the “authority” portion of a URL, in order to designate a port number (‘http://example.org:8080/’), an IPv6 address (‘http://[::1]/’), or a password (‘http://x:y@example.org/’). Colons that appear after the third slash in a URL are treated as path separators, as usual.

Many library functions accept an argument that is a pointer to a string, array, or structure of some kind. If the object pointed to is not modified, the argument is now declared with the const qualifier.

Previously, the putvec() function would sometimes modify the array provided by the caller; now, the array is never modified.

The sample() function will return correct results when samples are retrieved in random order. Previously, if the caller requested sample 1, followed by sample 5000, followed by sample 2, sample() would return sample 1, followed by sample 4998, followed by sample 5001.

A multi-segment record in which the first segment has non-zero length, but the first segment header file is missing length or checksum fields, is now handled correctly as a fixed-layout record.

setgvmode() will handle WFDB_GVPAD, as documented; this was broken in WFDB library versions 10.5.3 through 10.6.2.

getwfdb() will no longer add or modify existing environment variables. In previous versions of the library, the first time getwfdb() was called, it would set the WFDB, WFDBCAL, WFDBANNSORT, and WFDBGVMODE environment variables, if these variables were not already defined.

setwfdb() will correctly handle indirect paths (e.g., ‘@file’).

timstr() or mstimstr() would, in some cases, return an incorrect date following a call to setbasetime() or datstr(). This has been fixed.