1#@!#!123s

: / proc / thread-self / root / usr / share / doc / apr /

Filename : README.deepbind

back

This distribution of APR contains a modification of the behaviour of
the apr_dso_open() function which allows users enable the
"RTLD_DEEPBIND" flag when dlopen() is called.

If the "APR_DEEPBIND" environment variable is set at runtime, the
RTLD_DEEPBIND flag is always added to the flags passed to dlopen().

With normal use of dlopen(), dynamically loaded objects will use
global symbols in preference to any symbols defined within the object.
Using RTLD_DEEPBIND reverses this binding order.  See the dlopen(3)
man page for more information.

This can be useful with Apache httpd, where two different modules are
loaded like:

1. mod_foo.so uses library "libfoo.so"
   libfoo.so defines a function "SomeSym"
2. mod_bar.so uses library "libbar.so"
   libbar.so defines a different "SomeSym" function

By default, mod_bar or mod_foo would use the "SomeSym" definition from
the "wrong" library depending on the load order.  If RTLD_DEEPBIND is
used, the "SomeSym" definition will always be mapped to the definition
from the corresponding dependent library.  This can avoid symbol
conflicts.

There are some risks with using RTLD_DEEPBIND, in particular potential
issues with modules written in C++.  It is not recommended to enable
$APR_DEEPBIND unless it solves a specific problem and after thorough
testing of the configuration.

Name	Size	Last Modified	Owner	Permissions
CHANGES	5.293 KB	September 11 2017 3:28:41	root	0644
LICENSE	17.558 KB	October 21 2013 11:57:36	root	0644
NOTICE	0.515 KB	January 02 2017 7:43:47	root	0644
README	5.501 KB	March 01 2010 8:40:53	root	0644
README.cmake	4.399 KB	January 20 2014 2:16:10	root	0644
README.deepbind	1.299 KB	October 10 2021 12:35:46	root	0644
README.deepbind.deepbind	0 KB	October 10 2021 12:35:46	root	0644

2017 © D7net \| D704T team