C how to identify that mail has received

In C, there are several ways to identify that mail has been received:

Using the mail() function: The mail() function returns a value indicating whether the mail was sent successfully. You can check the return value to see if the mail was received.
```
#include <mail.h>
```

int main() { if (mail("[email protected]", "Subject", "Hello, world!") == 0) { printf("Mail sent successfully.\n"); } else { printf("Error sending mail.\n"); } return 0; }

2. **Using the `sendmail()` function**: The `sendmail()` function returns a value indicating whether the mail was sent successfully. You can check the return value to see if the mail was received.
```c
#include <sendmail.h>

int main() {
    if (sendmail("[email protected]", "Subject", "Hello, world!") == 0) {
        printf("Mail sent successfully.\n");
    } else {
        printf("Error sending mail.\n");
    }
    return 0;
}

Using the imap() function: The imap() function allows you to connect to an IMAP server and retrieve mail. You can use the imap_search() function to search for new mail and then use the imap_fetch() function to retrieve the mail.
```
#include <imap.h>
```

int main() { imap_t *imap = imap_open("imap.gmail.com", "username", "password"); if (imap) { imap_search(imap, "UNSEEN"); imap_fetch(imap, "1", "BODY[TEXT]"); imap_close(imap); } return 0; }

4. **Using the `pop3()` function**: The `pop3()` function allows you to connect to a POP3 server and retrieve mail. You can use the `pop3_list()` function to list the mail and then use the `pop3_retr()` function to retrieve the mail.
```c
#include <pop3.h>

int main() {
    pop3_t *pop3 = pop3_open("pop.gmail.com", "username", "password");
    if (pop3) {
        pop3_list(pop3);
        pop3_retr(pop3, "1", "BODY[TEXT]");
        pop3_close(pop3);
    }
    return 0;
}

Note that these examples are simplified and may not work as-is in your specific use case. You may need to modify them to fit your needs and handle errors properly. Additionally, you should always check the documentation for the specific mail library you are using to ensure you are using it correctly.

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C how to identify that mail has received