pam_get_data man page
pam_get_data — get module internal data
int pam_get_data(const pam_handle_t *pamh, const char *module_data_name, const void **data);
This function together with the pam_set_data(3) function is useful to manage module-specific data meaningful only to the calling PAM module.
The pam_get_data function looks up the object associated with the (hopefully) unique string module_data_name in the PAM context specified by the pamh argument. A successful call to pam_get_data will result in data pointing to the object. Note, this data is not a copy and should be treated as constant by the module.
Data was successful retrieved.
A NULL pointer was submitted as PAM handle or the function was called by an application.
Module data not found or there is an entry, but it has the value NULL.
pam_end(3), pam_set_data(3), pam_strerror(3)
pam(3), pam_end(3), pam_set_data(3), pam_start(3).