X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=FAQ;h=ecce985a44420b0df880ddfc8975d495e9061c1a;hp=29acc8afdf5be9f58c0bce13c58259e6b522414b;hb=f7a059316f4433cf339b5dce7ff034a9862df490;hpb=0e8f2fdfddd08b16c5240f881a232fbdc7af69ad

diff --git a/FAQ b/FAQ
index 29acc8afdf..ecce985a44 100644
--- a/FAQ
+++ b/FAQ
@@ -6,6 +6,7 @@ OpenSSL  -  Frequently Asked Questions
 * How can I contact the OpenSSL developers?
 * Do I need patent licenses to use OpenSSL?
 * Is OpenSSL thread-safe?
+* Can I use OpenSSL's SSL library with non-blocking I/O?
 * Why do I get a "PRNG not seeded" error message?
 * Why does the linker complain about undefined symbols?
 * Where can I get a compiled version of OpenSSL?
@@ -27,6 +28,8 @@ OpenSSL  -  Frequently Asked Questions
 * Why does the OpenSSL test fail with "bc: 1 no implemented"?
 * Why does the OpenSSL compilation fail on Alpha True64 Unix?
 * Why does the OpenSSL compilation fail with "ar: command not found"?
+* Why does the OpenSSL compilation fail on Win32 with VC++?
+* Why aren't tools like 'autoconf' and 'libtool' used?
 
 
 * Which is the current version of OpenSSL?
@@ -101,6 +104,20 @@ Multi-threaded applications must provide two callback functions to
 OpenSSL.  This is described in the threads(3) manpage.
 
 
+* Can I use OpenSSL's SSL library with non-blocking I/O?
+
+Yes; make sure to read the SSL_get_error(3) manual page!
+
+A pitfall to avoid: Don't assume that SSL_read() will just read from
+the underlying transport or that SSL_write() will just write to it --
+it is also possible that SSL_write() cannot do any useful work until
+there is data to read, or that SSL_read() cannot do anything until it
+is possible to send data.  One reason for this is that the peer may
+request a new TLS/SSL handshake at any time during the protocol,
+requiring a bi-directional message exchange; both SSL_read() and
+SSL_write() will try to continue any pending handshake.
+
+
 * Why do I get a "PRNG not seeded" error message?
 
 Cryptographic software needs a source of unpredictable data to work
@@ -430,3 +447,29 @@ and then redo the compilation.  What you should really do is make sure
 '/usr/ccs/bin' is permanently in your $PATH, for example through your
 '.profile' (again, assuming you use a sh-compatible shell).
 
+
+* Why does the OpenSSL compilation fail on Win32 with VC++?
+
+Sometimes, you may get reports from VC++ command line (cl) that it
+can't find standard include files like stdio.h and other weirdnesses.
+One possible cause is that the environment isn't correctly set up.
+To solve that problem, one should run VCVARS32.BAT which is found in
+the 'bin' subdirectory of the VC++ installation directory (somewhere
+under 'Program Files').  This needs to be done prior to running NMAKE,
+and the changes are only valid for the current DOS session.
+
+
+* Why aren't tools like 'autoconf' and 'libtool' used?
+
+autoconf is a nice tool, but is unfortunately very Unix-centric.
+Although one can come up with solution to have ports keep in track,
+there's also some work needed for that, and can be quite painful at
+times.  If there was a 'autoconf'-like tool that generated perl
+scripts or something similarly general, it would probably be used
+in OpenSSL much earlier.
+
+libtool has repeatadly been reported by some members of the OpenSSL
+development and others to be a pain to use.  So far, those in the
+development team who have said anything about this have expressed
+a wish to avoid libtool for that reason.
+