diff options
Diffstat (limited to 'crypto/openssl/doc/crypto/threads.pod')
| -rw-r--r-- | crypto/openssl/doc/crypto/threads.pod | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/crypto/openssl/doc/crypto/threads.pod b/crypto/openssl/doc/crypto/threads.pod index afa45cd..3df4ecd 100644 --- a/crypto/openssl/doc/crypto/threads.pod +++ b/crypto/openssl/doc/crypto/threads.pod @@ -65,9 +65,10 @@ 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 +id_function(void) is a function that returns a thread ID, for example +pthread_self() if it returns an integer (see NOTES below). It isn't needed on Windows nor on platforms where getpid() returns a different -ID for each thread (most notably Linux). +ID for each thread (see NOTES below). Additionally, OpenSSL supports dynamic locks, and sometimes, some parts of OpenSSL need it for better performance. To enable this, the following @@ -124,13 +125,13 @@ CRYPTO_get_new_dynlockid() returns the index to the newly created lock. The other functions return no values. -=head1 NOTE +=head1 NOTES You can find out if OpenSSL was configured with thread support: #define OPENSSL_THREAD_DEFINES #include <openssl/opensslconf.h> - #if defined(THREADS) + #if defined(OPENSSL_THREADS) // thread support enabled #else // no thread support @@ -139,6 +140,22 @@ You can find out if OpenSSL was configured with thread support: Also, dynamic locks are currently not used internally by OpenSSL, but may do so in the future. +Defining id_function(void) has it's own issues. Generally speaking, +pthread_self() should be used, even on platforms where getpid() gives +different answers in each thread, since that may depend on the machine +the program is run on, not the machine where the program is being +compiled. For instance, Red Hat 8 Linux and earlier used +LinuxThreads, whose getpid() returns a different value for each +thread. Red Hat 9 Linux and later use NPTL, which is +Posix-conformant, and has a getpid() that returns the same value for +all threads in a process. A program compiled on Red Hat 8 and run on +Red Hat 9 will therefore see getpid() returning the same value for +all threads. + +There is still the issue of platforms where pthread_self() returns +something other than an integer. This is a bit unusual, and this +manual has no cookbook solution for that case. + =head1 EXAMPLES B<crypto/threads/mttest.c> shows examples of the callback functions on |
