The pam_strerror() function maps the PAM error number in errnum to a PAM error message string, and returns a pointer to that string. The application should not free or modify the string returned.

The pamh argument is the PAM handle obtained by a prior call to pam_start(). If pam_start() returns an error, a null PAM handle should be passed.

The pam_strerror() function returns NULL if errnum is out-of-range.

See attributes(5) for description of the following attributes:

pam(3PAM), pam_start(3PAM), attributes(5)

The interfaces in libpam are MT-Safe only if each thread within the multithreaded application uses its own PAM handle.