comedi_errno
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## 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 by calling `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`.

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