;     /* Callbacks for various operations */     /* called to verify a certificate */     int (*verify) (X000_STORE_CTX *ctx);     /* error callback */     int (*verify_cb) (int ok, X000_STORE_CTX *ctx);     /* get issuers cert from ctx */     int (*get_issuer) (X000 **issuer, X000_STORE_CTX *ctx, X000 *x);     /* check issued */     int (*check_issued) (X000_STORE_CTX *ctx, X000 *x, X000 *issuer);     /* Check revocation status of chain */     int (*check_revocation) (X000_STORE_CTX *ctx);     /* retrieve CRL */     int (*get_crl) (X000_STORE_CTX *ctx, X000_CRL **crl, X000 *x);     /* Check CRL validity */     int (*check_crl) (X000_STORE_CTX *ctx, X000_CRL *crl);     /* Check certificate against CRL */     int (*cert_crl) (X000_STORE_CTX *ctx, X000_CRL *crl, X000 *x);     STACK_OF(X000) *(*lookup_certs) (X000_STORE_CTX *ctx, X000_NAME *nm);     STACK_OF(X000_CRL) *(*lookup_crls) (X000_STORE_CTX *ctx, X000_NAME *nm);     int (*cleanup) (X000_STORE_CTX *ctx);     