threads mapage.

is not one of these, consult the INSTALL file.

Multi-threaded applications must provide two callback functions to

OpenSSL.  This will be described in the threads(3) manpage.  [That

page has not been written yet.  Please read the "threads.doc" section

of doc/ssleay.txt instead.]

OpenSSL.  This is described in the threads(3) manpage.

* Why do I get a "PRNG not seeded" error message?

=pod

=head1 NAME

CRYPTO_set_locking_callback, CRYPTO_set_id_callback - OpenSSL thread support

=head1 SYNOPSIS

 #include <openssl/crypto.h>

 void CRYPTO_set_locking_callback(void (*locking_function)(int mode,

        int n, const char *file, int line));

 void CRYPTO_set_id_callback(unsigned long (*id_function)(void));

=head1 DESCRIPTION

OpenSSL can safely be used in multi-threaded applications provided

that two callback functions are set.

locking_function(int mode, int type, const char *file, int line) is

needed to perform locking on shared data stuctures. Multi-threaded

applications will crash at random if it is not set.

locking_function() must be able to handle up to B<CRYPTO_NUM_LOCKS>

different mutex locks. It sets the B<n>th lock if B<mode> &

B<CRYPTO_LOCK>, and releases it otherwise.

B<file> and B<line> are the file number of the function setting the

lock. They can be useful for debugging.

id_function(void) is a function that returns a thread ID. It is not

needed on Windows nor on platforms where getpid() returns a different

ID for each thread.

=NOTE

You can find out if OpenSSL was configured with thread support:

 #define OPENSSL_THREAD_DEFINES

 #include <openssl/opensslconf.h>

 #if defined(THREADS)

   // thread support enabled

 #else

   // no thread support

 #endif

=head1 EXAMPLES

B<crypto/threads/mttest.c> shows examples of the callback functions on

Solaris, Irix and Win32.

=head1 HISTORY

CRYPTO_set_locking_callback() and CRYPTO_set_id_callback() are

available in all versions of SSLeay and OpenSSL.

=head1 SEE ALSO

L<crypto(3)|crypto(3)>

=cut