Setting PASSWDFUNCTION to NULL will set back the internal function as password

Pass a pointer to a \fIcurl_passwd_callback\fP function that will be called

instead of the internal one if libcurl requests a password. The function must

match this prototype: \fBint my_getpass(void *client, char *prompt, char*

buffer, int buflen );\fP.  If set to NULL, it equals to making the function

always fail. If the function returns a non-zero value, it will abort the

operation and an error (CURLE_BAD_PASSWORD_ENTERED) will be returned.

buffer, int buflen );\fP.  If set to NULL, it sets back the function to the

internal default one. If the function returns a non-zero value, it will abort

the operation and an error (CURLE_BAD_PASSWORD_ENTERED) will be returned.

\fIclient\fP is a generic pointer, see \fICURLOPT_PASSWDDATA\fP.  \fIprompt\fP

is a zero-terminated string that is text that prefixes the input request.

\fIbuffer\fP is a pointer to data where the entered password should be stored