---
name: "modbus_strerror"
section: "3"
platform: "linux"
package: "libmodbus-dev"
version: "3.1.6-2.1"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/modbus_strerror"
---

# modbus\_strerror(3)

return the error message

## NAME

modbus\_strerror - return the error message

## SYNOPSIS

**const char \*modbus\_strerror(int** *errnum***);**

## DESCRIPTION

The **modbus\_strerror()** function shall return a pointer to an error message string corresponding to the error number specified by the *errnum* argument. As libmodbus defines additional error numbers over and above those defined by the operating system, applications should use **modbus\_strerror()** in preference to the standard **strerror()** function.

## RETURN VALUE

The **modbus\_strerror()** function shall return a pointer to an error message string.

## ERRORS

No errors are defined.

## EXAMPLE

**Display an error message when a Modbus connection cannot be established**.

```
if (modbus_connect(ctx) == -1) {
    fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
    abort();
}
```

## SEE ALSO

linkmb:libmodbus

## AUTHORS

The libmodbus documentation was written by Stéphane Raimbault \<stephane.raimbault@gmail.com\>