comedi_perror

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_perror() prints an error message to stderr. The error message consists of the argument string, a colon, a space, a description of the error condition, and a new line.