centos man page for x509_verify_cert

X509_verify_cert(3)						      OpenSSL						       X509_verify_cert(3)

NAME
       X509_verify_cert - discover and verify X509 certificte chain

SYNOPSIS
	#include <openssl/x509.h>

	int X509_verify_cert(X509_STORE_CTX *ctx);

DESCRIPTION
       The X509_verify_cert() function attempts to discover and validate a certificate chain based on parameters in ctx. A complete description of
       the process is contained in the verify(1) manual page.

RETURN VALUES
       If a complete chain can be built and validated this function returns 1, otherwise it return zero, in exceptional circumstances it can also
       return a negative code.

       If the function fails additional error information can be obtained by examining ctx using, for example X509_STORE_CTX_get_error().

NOTES
       Applications rarely call this function directly but it is used by OpenSSL internally for certificate validation, in both the S/MIME and
       SSL/TLS code.

       The negative return value from X509_verify_cert() can only occur if no certificate is set in ctx (due to a programming error) or if a retry
       operation is requested during internal lookups (which never happens with standard lookup methods). It is however recommended that
       application check for <= 0 return value on error.

BUGS
       This function uses the header x509.h as opposed to most chain verification functiosn which use x509_vfy.h.

SEE ALSO
       X509_STORE_CTX_get_error(3)

HISTORY
       X509_verify_cert() is available in all versions of SSLeay and OpenSSL.

1.0.1e								    2013-02-11						       X509_verify_cert(3)