# err.h - [Overview](#section832343483165627) - [Summary](#section1715116744165627) - [Functions](#func-members) ## **Overview** **Related Modules:** [IO](io.md) **Description:** Provides common functions for error messages. You can use the functions provided in this file to implement error output operations required during development. **Since:** 1.0 **Version:** 1.0 ## **Summary** ## Functions

Function	Description
warn (const char *fmt,...)	void Displays a formatted error message on the standard error (stderr) output.
vwarn (const char *fmt, va_list args)	void Displays a formatted error message on the stderr output.
warnx (const char *fmt,...)	void Displays a formatted error message on the stderr output.
vwarnx (const char *fmt, va_list args)	void Displays a formatted error message on the stderr output.
err (int eval, const char *fmt, va_list args)	void Displays error information.
errx (int eval, const char *fmt,...)	void Displays error information.
verr (int eval, const char *fmt, va_list args)	void Displays error information.
verrx (int eval, const char *fmt, va_list args)	void Displays a formatted error message.