| =pod |
| |
| =head1 NAME |
| |
| CRYPTO_THREAD_lock_new, CRYPTO_THREAD_read_lock, CRYPTO_THREAD_write_lock, |
| CRYPTO_THREAD_unlock, CRYPTO_THREAD_lock_free, CRYPTO_atomic_add - OpenSSL thread support |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/crypto.h> |
| |
| CRYPTO_RWLOCK *CRYPTO_THREAD_lock_new(void); |
| int CRYPTO_THREAD_read_lock(CRYPTO_RWLOCK *lock); |
| int CRYPTO_THREAD_write_lock(CRYPTO_RWLOCK *lock); |
| int CRYPTO_THREAD_unlock(CRYPTO_RWLOCK *lock); |
| void CRYPTO_THREAD_lock_free(CRYPTO_RWLOCK *lock); |
| |
| int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock); |
| |
| =head1 DESCRIPTION |
| |
| OpenSSL can be safely used in multi-threaded applications provided that |
| support for the underlying OS threading API is built-in. Currently, OpenSSL |
| supports the pthread and Windows APIs. OpenSSL can also be built without |
| any multi-threading support, for example on platforms that don't provide |
| any threading support or that provide a threading API that is not yet |
| supported by OpenSSL. |
| |
| The following multi-threading function are provided: |
| |
| =over 4 |
| |
| =item * |
| CRYPTO_THREAD_lock_new() allocates, initializes and returns a new read/write |
| lock. |
| |
| =item * |
| CRYPTO_THREAD_read_lock() locks the provided B<lock> for reading. |
| |
| =item * |
| CRYPTO_THREAD_write_lock() locks the provided B<lock> for writing. |
| |
| =item * |
| CRYPTO_THREAD_unlock() unlocks the previously locked B<lock>. |
| |
| =item * |
| CRYPTO_THREAD_lock_frees() frees the provided B<lock>. |
| |
| =item * |
| CRYPTO_atomic_add() atomically adds B<amount> to B<val> and returns the |
| result of the operation in B<ret>. B<lock> will be locked, unless atomic |
| operations are supported on the specific platform. Because of this, if a |
| variable is modified by CRYPTO_atomic_add() then CRYPTO_atomic_add() must |
| be the only way that the variable is modified. |
| |
| =back |
| |
| =head1 RETURN VALUES |
| |
| CRYPTO_THREAD_lock_new() returns the allocated lock, or NULL on error. |
| |
| CRYPTO_THREAD_lock_frees() returns no value. |
| |
| The other functions return 1 on success or 0 on error. |
| |
| =head1 NOTES |
| |
| You can find out if OpenSSL was configured with thread support: |
| |
| #define OPENSSL_THREAD_DEFINES |
| #include <openssl/opensslconf.h> |
| #if defined(OPENSSL_THREADS) |
| // thread support enabled |
| #else |
| // no thread support |
| #endif |
| |
| =head1 SEE ALSO |
| |
| L<crypto(3)> |
| |
| =cut |
