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

Question

Why use the link for the mysqlclient library? What is the difference between the two? I can't seem to find the answer. Thank.

Answer 1

libmysqlclient_r.a is thread safe

Answer 2

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

Answer 3

libmysqlclient_r.a " ". https://en.wikipedia.org/wiki/Reentrant_%28subroutine%29 , , ( ).

Answer 4

libmysqlclient_r is guaranteed to be thread safe for every connection. However, MySQL documentation prior to MySQL 5.5 is unclear as to whether multithreaded applications can reference libmysqlclient if there is no simultaneous access to a single MySQL connection descriptor.

Based on experience, I used libmysqlclient for applications that process 100-400 queries per second and work for 5 years. I have not encountered any problems yet.