freebsd man page for err_get_lib

ERR_GET_LIB(3SSL)                                                     OpenSSL                                                    ERR_GET_LIB(3SSL)

NAME
       ERR_GET_LIB, ERR_GET_FUNC, ERR_GET_REASON - get library, function and reason code

SYNOPSIS
        #include <openssl/err.h>

        int ERR_GET_LIB(unsigned long e);

        int ERR_GET_FUNC(unsigned long e);

        int ERR_GET_REASON(unsigned long e);

DESCRIPTION
       The error code returned by ERR_get_error() consists of a library number, function code and reason code. ERR_GET_LIB(), ERR_GET_FUNC() and
       ERR_GET_REASON() can be used to extract these.

       The library number and function code describe where the error occurred, the reason code is the information about what went wrong.

       Each sub-library of OpenSSL has a unique library number; function and reason codes are unique within each sub-library.  Note that different
       libraries may use the same value to signal different functions and reasons.

       ERR_R_... reason codes such as ERR_R_MALLOC_FAILURE are globally unique. However, when checking for sub-library specific reason codes, be
       sure to also compare the library number.

       ERR_GET_LIB(), ERR_GET_FUNC() and ERR_GET_REASON() are macros.

RETURN VALUES
       The library number, function code and reason code respectively.

SEE ALSO
       err(3), ERR_get_error(3)

HISTORY
       ERR_GET_LIB(), ERR_GET_FUNC() and ERR_GET_REASON() are available in all versions of SSLeay and OpenSSL.

1.0.1e                                                              2013-02-11                                                   ERR_GET_LIB(3SSL)