> From: owner-openssl-us...@openssl.org On Behalf Of marek.marc...@malkom.pl > Sent: Monday, 21 May, 2012 11:11 (-dev dropped)
> This looks like declaration mismatch, you should send more info (used > compilers, environment), maybe simple test code. > owner-openssl-us...@openssl.org wrote on 05/21/2012 02:52:15 PM: > > Cannot assign extern "C" void(*)(ssl_st*,int,int) to extern "C" > void(*)() at a line where we have > > "SSL_CTX_set_info_callback(ctx, ssl_connection_info_cb);" > > > > We are doing the same as mentioned in the below mail chain. > > > > Can you pleas help us in resolving this. Thanks in advance. > > What version of openssl? All the versions I have back to early 0.9.8 declare SSL_CTX_set_info_callback to take void(*)(const SSL*,int,int). I have a few 0.9.7 versions that make it a macro which assigns to (ctx)->info_callback, but that is declared the same way. If you have a very old openssl that uses the K&R1-style declaration void(*cb)(), this exposes an incompatibility between C++ and C. In C () still has the K&R1 meaning of 'unknown (but non-vararg default-promoted) arguments' and only (void) means 'no arguments'. In C++ either (void) or () means 'no arguments'. If you are using such an old version, you'll need to make the part of your app that calls _set_info_callback C instead of C++. (If you don't want to convert much/all, you could write a 2-line C wrapper that is called from your C++.) But much better use a newer version that has better security _and_ support. Also note your callback should have its first parameter a pointer to >const< SSL or equivalently const struct ssl_st, or in C++ just const ssl_st (but in C++ the whole function must be extern "C"). In both C++ and C a pointer to const T and a pointer to nonconst T are formally incompatible, although in practice they interchange. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
