The
pam_chauthtok function attempts to change the authentication token for the user associated with the pam context specified by the
pamh argument.
The
flags argument is the binary or of zero or more of the following values:
PAM_SILENT
Do not emit any messages.
PAM_CHANGE_EXPIRED_AUTHTOK
Change only those authentication tokens that have expired.
If any other bits are set,
pam_chauthtok will return
PAM_SYMBOL_ERR.