php – OpenSSL是否真的需要openssl.conf的路径？

官方PHP Manual说：

By default,the information in your system openssl.conf is used to initialize the request; you can specify a configuration file section by setting the config_section_section key of configargs. You can also specify an alternative openssl configuration file by setting the value of the config key to the path of the file you want to use. The following keys,if present in configargs behave as their equivalents in the openssl.conf,as listed in the table below…..

我的问题：是否有一个原因我必须明确指定openssl.conf的路径,因为它似乎工作正常没有它：

$Configs = array(       
    'digest_alg' => 'sha1','x509_extensions' => 'v3_ca','req_extensions' => 'v3_req','private_key_bits' => 1024,'private_key_type' => OPENSSL_KEYTYPE_RSA,'encrypt_key' => true,'encrypt_key_cipher' => OPENSSL_CIPHER_3DES
);

$privkey = openssl_pkey_new();
$csr = openssl_csr_new($dn,$privkey,$Configs);
$sscert = openssl_csr_sign($csr,null,365,$Configs);

编辑：

用户在PHP Manual上提供了笔记,为什么总是指定openssl.cnf的路径？例如：

$configargs = array(
    'config' => '/etc/ssl/openssl.cnf','digest_alg' => 'md5','req_extensions'   => 'v3_req','private_key_bits' => 666,'encrypt_key' => false,);