avr-libc: <errno.h>: System Errors

avr-libc 2.0.0 Standard C library for AVR-GCC |

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<errno.h>: System Errors

## Macros
#define | EDOM 33
#define | ERANGE 34

## Variables
int | errno

## Detailed Description

#include <errno.h>

Some functions in the library set the global variable `errno` when an error occurs. The file, `<errno.h>`, provides symbolic names for various error codes.

## Macro Definition Documentation

## ◆ EDOM

#define EDOM 33

Domain error.

## ◆ ERANGE

#define ERANGE 34

Range error.

## Variable Documentation

## ◆ errno

int errno
| extern

Error code for last error encountered by library.

The variable `errno` holds the last error code encountered by a library function. This variable must be cleared by the user prior to calling a library function.

Warning
  The `errno` global variable is not safe to use in a threaded or multi-task system. A race condition can occur if a task is interrupted between the call which sets `error` and when the task examines `errno`. If another task changes `errno` during this time, the result will be incorrect for the interrupted task.

errno.h