Change the RAND_file_name documentation accordingly

[openssl.git] / doc / crypto / BIO_f_md.pod

diff --git a/doc/crypto/BIO_f_md.pod b/doc/crypto/BIO_f_md.pod
index ebca9440654bc20c2e191417c8d108cf6890bc7b..b2c1433d25b3e68724664a47f9e205f1ccd32235 100644 (file)
--- a/doc/crypto/BIO_f_md.pod
+++ b/doc/crypto/BIO_f_md.pod
@@ -4,15 +4,17 @@
 
 BIO_f_md, BIO_set_md, BIO_get_md, BIO_get_md_ctx - message digest BIO filter
 
+=for comment multiple includes
+
 =head1 SYNOPSIS
 
  #include <openssl/bio.h>
  #include <openssl/evp.h>
 
- BIO_METHOD *  BIO_f_md(void);
- int BIO_set_md(BIO *b,EVP_MD *md);
- int BIO_get_md(BIO *b,EVP_MD **mdp);
- int BIO_get_md_ctx(BIO *b,EVP_MD_CTX **mdcp);
+ const BIO_METHOD *BIO_f_md(void);
+ int BIO_set_md(BIO *b, EVP_MD *md);
+ int BIO_get_md(BIO *b, EVP_MD **mdp);
+ int BIO_get_md_ctx(BIO *b, EVP_MD_CTX **mdcp);
 
 =head1 DESCRIPTION
 
@@ -28,7 +30,7 @@ BIO_gets(), if its B<size> parameter is large enough finishes the
 digest calculation and returns the digest value. BIO_puts() is
 not supported.
 
-BIO_reset() reinitializes a digest BIO.
+BIO_reset() reinitialises a digest BIO.
 
 BIO_set_md() sets the message digest of BIO B<b> to B<md>: this
 must be called to initialize a digest BIO before any data is
@@ -58,6 +60,10 @@ If an application needs to call BIO_gets() or BIO_puts() through
 a chain containing digest BIOs then this can be done by prepending
 a buffering BIO.
 
+Calling BIO_get_md_ctx() will return the context and initialize the BIO
+state. This allows applications to initialize the context externally
+if the standard calls such as BIO_set_md() are not sufficiently flexible.
+
 =head1 RETURN VALUES
 
 BIO_f_md() returns the digest BIO method.
@@ -99,7 +105,7 @@ The next example digests data by reading through a chain instead:
  BIO_set_md(mdtmp, EVP_md5());
  bio = BIO_push(mdtmp, bio);
  do {
-       rdlen = BIO_read(bio, buf, sizeof(buf));
+        rdlen = BIO_read(bio, buf, sizeof(buf));
         /* Might want to do something with the data here */
  } while(rdlen > 0);
 
@@ -110,29 +116,41 @@ outputs them. This could be used with the examples above.
  unsigned char mdbuf[EVP_MAX_MD_SIZE];
  int mdlen;
  int i;
- mdtmp = bio;  /* Assume bio has previously been set up */
+ mdtmp = bio;   /* Assume bio has previously been set up */
  do {
-       EVP_MD *md;
-       mdtmp = BIO_find_type(mdtmp, BIO_TYPE_MD);
+        EVP_MD *md;
+        mdtmp = BIO_find_type(mdtmp, BIO_TYPE_MD);
         if(!mdtmp) break;
-       BIO_get_md(mdtmp, &md);
+        BIO_get_md(mdtmp, &md);
         printf("%s digest", OBJ_nid2sn(EVP_MD_type(md)));
-       mdlen = BIO_gets(mdtmp, mdbuf, EVP_MAX_MD_SIZE);
-       for(i = 0; i < mdlen; i++) printf(":%02X", mdbuf[i]);
-       printf("\n");
-       mdtmp = BIO_next(mdtmp);
+        mdlen = BIO_gets(mdtmp, mdbuf, EVP_MAX_MD_SIZE);
+        for(i = 0; i < mdlen; i++) printf(":%02X", mdbuf[i]);
+        printf("\n");
+        mdtmp = BIO_next(mdtmp);
  } while(mdtmp);
 
  BIO_free_all(bio);
 
 =head1 BUGS
 
-The lack of support for BIO_puts() and the non standard behavior of
+The lack of support for BIO_puts() and the non standard behaviour of
 BIO_gets() could be regarded as anomalous. It could be argued that BIO_gets()
 and BIO_puts() should be passed to the next BIO in the chain and digest
 the data passed through and that digests should be retrieved using a
 separate BIO_ctrl() call.
 
-=head1 SEE ALSO
+=head1 HISTORY
+
+Before OpenSSL 1.0.0., the call to BIO_get_md_ctx() would only work if the
+BIO was initialized first.
+
+=head1 COPYRIGHT
+
+Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the OpenSSL license (the "License").  You may not use
+this file except in compliance with the License.  You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
 
-TBA
+=cut