Liberating a locally saved environment
#include <security/pam_misc.h>
int pam_misc_drop_env(char **env);
This function is defined to complement the pam_getenvlist(3) function. It liberates the memory associated with env, overwriting with 0 all memory before free()ing it.
pam_getenvlist(3), pam(7)
The pam_misc_drop_env function is part of the libpam_misc Library and not defined in any standard.