From 9ad4c53515deb182c35a9438751b132594e7a739 Mon Sep 17 00:00:00 2001 From: DJ Delorie Date: Mon, 2 Dec 2019 15:32:10 -0500 Subject: [PATCH] ldconfig.8: Document file filter and symlink pattern expectations Information gleaned from comments in glibc's elf/ldconfig.c Signed-off-by: Michael Kerrisk --- man8/ldconfig.8 | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/man8/ldconfig.8 b/man8/ldconfig.8 index 4f799962c..15585243c 100644 --- a/man8/ldconfig.8 +++ b/man8/ldconfig.8 @@ -93,6 +93,28 @@ option. .B ldconfig should normally be run by the superuser as it may require write permission on some root owned directories and files. +.PP +Note that +.B ldconfig +will only look at files that are named +.I lib*.so* +(for regular shared objects) or +.I ld-*.so* +(for the dynamic loader itsef). Other files will be ignored. Also, +.B ldconfig +expects a certain pattern to how the symlinks are set up, like this +example, where the middle file +.RB ( libfoo.so.1 +here) is the SONAME for the library: +.PP +.in +4n +.EX +libfoo.so -> libfoo.so.1 -> libfoo.so.1.12 +.EE +.in +.PP +Failure to follow this pattern may result in compatibility issues +after an upgrade. .SH OPTIONS .TP .BR \-c " \fIfmt\fP, " \-\-format=\fIfmt\fP