Commit f25825c2 authored by Rich Salz's avatar Rich Salz Committed by Rich Salz
Browse files

Fix FAQ formatting for new website. 



Reviewed-by: default avatarMatt Caswell <matt@openssl.org>
parent ac63710a

FAQ

+16 −10
Original line number Diff line number Diff line
@@ -861,22 +861,25 @@ with the i2d_*_bio() or d2i_*_bio() functions or you can use the 
i2d_*(), d2i_*() functions directly. Since these are often the

cause of grief here are some code fragments using PKCS7 as an example:



----- snip:start -----

 unsigned char *buf, *p;

 int len;

 int len = i2d_PKCS7(p7, NULL);



 len = i2d_PKCS7(p7, NULL);

 buf = OPENSSL_malloc(len); /* or Malloc, error checking omitted */

 buf = OPENSSL_malloc(len); /* error checking omitted */

 p = buf;

 i2d_PKCS7(p7, &p);

----- snip:end -----



At this point buf contains the len bytes of the DER encoding of

p7.



The opposite assumes we already have len bytes in buf:



 unsigned char *p;

 p = buf;

----- snip:start -----

 unsigned char *p = buf;



 p7 = d2i_PKCS7(NULL, &p, len);

----- snip:end -----



At this point p7 contains a valid PKCS7 structure or NULL if an error

occurred. If an error occurred ERR_print_errors(bio) should give more
@@ -893,14 +896,17 @@ because it no longer points to the same address. 
Memory allocation and encoding can also be combined in a single

operation by the ASN1 routines:



 unsigned char *buf = NULL;	/* mandatory */

 int len;

 len = i2d_PKCS7(p7, &buf);

 if (len < 0)

----- snip:start -----

 unsigned char *buf = NULL;

 int len = i2d_PKCS7(p7, &buf);



 if (len < 0) {

     /* Error */

 }

 /* Do some things with 'buf' */

 /* Finished with buf: free it */

 OPENSSL_free(buf);

----- snip:end -----



In this special case the "buf" parameter is *not* incremented, it points

to the start of the encoding.