[CentOS] Static linking against glibc
anandb at ripe.net
Mon Jun 25 12:39:05 UTC 2007
I'm building an RPM of a DNS server called NSD on CentOS 4.4. I'm going to
be using it for some heavy-duty DNS traffic, so I want to minimise its
dependencies on external libraries. I have therefore attempted to link it
The package does build, and even runs fine. However, during the build
process, gcc emits warnings like these:
nsd.o(.text+0xfba): In function `main':
: warning: Using 'getpwnam' in statically linked applications requires at
runtime the shared libraries from the glibc version used for linking
My understanding of this is because glibc uses dlopen to load other shared
objects at runtime. I therefore need a Requires: line in the RPM which
requires glibc-2.3.4-2.36, or whatever version I used to build nsd.
Now, what I want to ask is: if the version of glibc is upgraded to say
2.3.4-2.48, what happens? What do the numbers after the version number
mean (2.48) and what effect will that have on packages which are
statically linked against glibc?
Another question which has occured to me is this: NSD also uses other
libraries, such as openssl. Is there any way to know if any of the
openssl libraries use dlopen to load in other shared objects? If they do,
then it introduces dependencies that I may not be aware of, and doing
static linking wouldn't be as beneficial as I first thought it would be.
Comments from experienced developers will be most appreciated.
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