What is difference between libmysqlclient.a and libmysqlclient_r.a?

Which should I use to link for mysqlclient library? What开发者_如何学Go is the difference between them? I can't seem to find the answer. Thanks.

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Newer versions of the MySQL client distributions do not include the "_r" version. Some may have a symbolic link from libmyqslclient_r.a to libmyqslclient.a

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libmysqlclient_r.a is thread-safe

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libmysqlclient_r.a is "re-entrant". https://en.wikipedia.org/wiki/Reentrant_%28subroutine%29 But as Garret pointed out, there is no difference in newer versions (both are re-entrant).

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libmysqlclient_r is guaranteed to be thread-safe per connection. However, MySQL documentations prior to MySQL 5.5 are vague on whether multi-threaded applications can link to libmysqlclient as long as there are no simultaneous access on a single MySQL connection handle.

Base on experience though, I used libmysqlclient for applications that processes 100-400 queries per second and have been running for 5 years. I've yet to encounter any issues.