=pod =head1 NAME CRYPTO_set_locking_callback, CRYPTO_set_id_callback - OpenSSL thread support =head1 SYNOPSIS #include 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)); int CRYPTO_num_locks(void); =head1 DESCRIPTION OpenSSL can safely be used in multi-threaded applications provided that two callback functions are set. locking_function(int mode, int n, 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 CRYPTO_num_locks() different mutex locks. It sets the B-th lock if B & B, and releases it otherwise. B and B 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 (most notably Linux). =head1 RETURN VALUES CRYPTO_num_locks() returns the required number of locks. The other functions return no values. =head1 NOTE You can find out if OpenSSL was configured with thread support: #define OPENSSL_THREAD_DEFINES #include #if defined(THREADS) // thread support enabled #else // no thread support #endif =head1 EXAMPLES B 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. CRYPTO_num_locks() was added in OpenSSL 0.9.4. =head1 SEE ALSO L =cut