NAME
comedi_errno - number of last Comedilib error
SYNOPSIS
#include <comedilib.h>
int comedi_errno (void );
DESCRIPTION
When a Comedilib function fails, it usually returns -1 or NULL,
depending on the return type. An internal library variable stores an
error number, which can be retrieved with comedi_errno(). This error
number can be converted to a human-readable form by the functions
comedi_perror() and comedi_strerror().
These functions are intended to mimic the behavior of the standard C
library functions perror(), strerror(), and errno. In particular,
Comedilib functions sometimes return an error that is generated inside
the C library; the comedi error message in this case is the same as the
C library.
The function comedi_errno() returns an integer describing the most
recent comedilib error. This integer may be used as the errnum
parameter for comedi_strerror().
Note that comedi_errno() is deliberately different than the variable
errno. This is to overcome difficulties in making errno thread-safe.
28 October 2007