Linux provides two functions for formatting error messages

#include "stdio.h"

Void perror (__const char *__s);

Where __s is where the error occurs, the function outputs to the standard error output device as follows: S: Error details.

Eg.perror ("fopen");

Output result: Fopen:no such file or directory.

#include "string.h"

Char *strerror (int __errnum);

__errnum refers to the error code, you can use the errno directly. The Strerror function does not directly output the error message, but instead returns a pointer to the detailed error message.

Note: Content in errno should be used immediately after an error, because if you do not use it immediately after an error, you may have an error when calling other functions, causing the original contents of the errno to be overwritten.

Linux provides two functions for formatting error messages