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https://github.com/openssl/openssl.git
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71 lines
1.8 KiB
Plaintext
71 lines
1.8 KiB
Plaintext
=pod
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=head1 NAME
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CRYPTO_set_locking_callback, CRYPTO_set_id_callback - OpenSSL thread support
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=head1 SYNOPSIS
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#include <openssl/crypto.h>
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void CRYPTO_set_locking_callback(void (*locking_function)(int mode,
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int n, const char *file, int line));
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void CRYPTO_set_id_callback(unsigned long (*id_function)(void));
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int CRYPTO_num_locks(void);
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=head1 DESCRIPTION
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OpenSSL can safely be used in multi-threaded applications provided
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that two callback functions are set.
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locking_function(int mode, int n, const char *file, int line) is
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needed to perform locking on shared data stuctures. Multi-threaded
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applications will crash at random if it is not set.
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locking_function() must be able to handle up to CRYPTO_num_locks()
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different mutex locks. It sets the B<n>-th lock if B<mode> &
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B<CRYPTO_LOCK>, and releases it otherwise.
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B<file> and B<line> are the file number of the function setting the
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lock. They can be useful for debugging.
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id_function(void) is a function that returns a thread ID. It is not
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needed on Windows nor on platforms where getpid() returns a different
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ID for each thread (most notably Linux).
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=head1 RETURN VALUES
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CRYPTO_num_locks() returns the required number of locks.
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The other functions return no values.
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=head1 NOTE
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You can find out if OpenSSL was configured with thread support:
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#define OPENSSL_THREAD_DEFINES
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#include <openssl/opensslconf.h>
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#if defined(THREADS)
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// thread support enabled
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#else
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// no thread support
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#endif
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=head1 EXAMPLES
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B<crypto/threads/mttest.c> shows examples of the callback functions on
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Solaris, Irix and Win32.
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=head1 HISTORY
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CRYPTO_set_locking_callback() and CRYPTO_set_id_callback() are
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available in all versions of SSLeay and OpenSSL.
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CRYPTO_num_locks() was added in OpenSSL 0.9.4.
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=head1 SEE ALSO
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L<crypto(3)|crypto(3)>
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=cut
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