lfs-book/appendixa/glibc-desc.xml

<sect2><title>Contents of Glibc</title>

<para>Last checked against version &glibc-contversion;.</para>

<sect3><title>Program Files</title>

<para>catchsegv, gencat, getconf, getent, glibcbug, iconv, iconvconfig,
ldconfig, ldd, lddlibc4, locale, localedef, mtrace, nscd, nscd_nischeck,
pcprofiledump, pt_chown, rpcgen, rpcinfo, sln, sprof, tzselect, xtrace,
zdump and zic</para></sect3>

<sect3><title>Descriptions</title>

<sect4><title>catchsegv</title>
<para>catchsegv can be used to create a stack trace when a program
terminates with a segmentation fault.</para></sect4>

<sect4><title>gencat</title>
<para>gencat generates message catalogues.</para></sect4>

<sect4><title>getconf</title>
<para>getconf displays the system configuration values for filesystem
specific variables.</para></sect4>

<sect4><title>getent</title>
<para>getent gets entries from an administrative database.</para></sect4>

<sect4><title>glibcbug</title>
<para>glibcbug creates a bug report about glibc and and mails it to the 
bug email address.</para></sect4>

<sect4><title>iconv</title>
<para>iconv performs character set conversion.</para></sect4>

<sect4><title>iconvconfig</title>
<para>iconvconfig creates fastloading iconv module 
configuration file.</para></sect4>

<sect4><title>ldconfig</title>
<para>ldconfig configures the dynamic linker run time bindings.</para></sect4>

<sect4><title>ldd</title>
<para>ldd prints the shared libraries required by each program or shared
library specified on the command line.</para></sect4>

<sect4><title>lddlibc4</title>
<para>lddlibc4 assists ldd with object files.</para></sect4>

<sect4><title>locale</title>
<para>locale is a Perl program which tells the compiler to enable
(or disable) the use of POSIX locales for built-in operations.</para></sect4>

<sect4><title>localedef</title>
<para>localedef compiles locale specifications.</para></sect4>

<sect4><title>mtrace</title>
<para>mtrace prints the multicast path from a source to a receiver (an IP
trace query).</para></sect4>

<sect4><title>nscd</title>
<para>nscd is a daemon that provides a cache for the most common name
service requests.</para></sect4>

<sect4><title>nscd_nischeck</title>
<para>nscd_nischeck checks whether or not secure mode is necessary for
NIS+ lookup.</para></sect4>

<sect4><title>pcprofiledump</title>
<para>pcprofiledump dumps information generated by 
PC profiling.</para></sect4>

<sect4><title>pt_chown</title>
<para>pt_chown sets the owner, group and access permission of the
slave pseudo terminal corresponding to the master pseudo terminal passed 
on file descriptor `3'. This is the helper program for the `grantpt' 
function. It is not intended to be run directly from the command
line.</para></sect4>

<sect4><title>rpcgen</title>
<para>rpcgen generates C code to implement the RPC protocol.</para></sect4>

<sect4><title>rpcinfo</title>
<para>rpcinfo makes an RPC call to an RPC server.</para></sect4>

<sect4><title>sln</title>
<para>sln symbolically links dest to source. It is statically linked,
needing no dynamic linking at all. Thus sln is useful to make symbolic 
links to dynamic libraries if the dynamic linking system for some reason 
is nonfunctional.</para></sect4>

<sect4><title>sprof</title>
<para>sprof reads and displays shared object profiling data.</para></sect4>

<sect4><title>tzselect</title>
<para>tzselect asks the user for information about the current location and 
outputs the resulting time zone description to standard output.</para></sect4>

<sect4><title>xtrace</title>
<para>xtrace traces execution of program by printing the currently executed
function.</para></sect4>

<sect4><title>zdump</title>
<para>zdump is the time zone dumper.</para></sect4>

<sect4><title>zic</title>
<para>zic is the time zone compiler.</para></sect4>

</sect3>

<sect3><title>Library Files</title>
<para>ld.so, libBrokenLocale.[a,so], libBrokenLocale_p.a,
libSegFault.so, libanl.[a,so], libanl_p.a, libbsd-compat.a, libc.[a,so],
libc_nonshared.a, libc_p.a, libcrypt.[a,so], libcrypt_p.a, libdl.[a,so],
libdl_p.a, libg.a, libieee.a, libm.[a,so], libm_p.a, libmcheck.a,
libmemusage.so, libnsl.a, libnsl_p.a, libnss_compat.so, libnss_dns.so,
libnss_files.so, libnss_hesiod.so, libnss_nis.so, libnss_nisplus.so,
libpcprofile.so, libpthread.[a,so], libpthread_p.a, libresolv.[a,so],
libresolv_p.a, librpcsvc.a, librpcsvc_p.a, librt.[a,so], librt_p.a,
libthread_db.so, libutil.[a,so] and libutil_p.a</para></sect3>

<sect3><title>Descriptions</title>

<sect4><title>ld.so</title>
<para>ld.so is the helper program for shared library 
executables.</para></sect4>

<sect4><title>libBrokenLocale, libBrokenLocale_p</title>
<para>Used by software, such as Mozilla, to solve broken locales.</para></sect4>

<sect4><title>libSegFault</title>
<para>libSegFault is a segmentation fault signal handler. It tries to catch
segfaults.</para></sect4>

<sect4><title>libanl, libanl_p</title>
<para>libanl is an asynchronous name lookup library.</para></sect4>

<sect4><title>libbsd-compat</title>
<para>libbsd-compat provides the portability needed in order to run certain
programs in Linux.</para></sect4>

<sect4><title>libc, libc_nonshared, libc_p</title>
<para>These files constitute the main C library. The C library is a
collection of commonly used functions in programs.
This way a programmer doesn't need to create his own functions for every
single task. The most common things like writing a string to the screen
are already present and at the disposal of the programmer.</para>

<para>The C library (actually almost every library) comes in two flavors:
a dynamic and a static one. In short, when a program uses a static C
library, the code from the C library is copied into the executable file.
When a program uses a dynamic library, the executable will not
contain the code from the C library, but instead a routine that loads
the functions from the library at the time the program is run. This
means a significant decrease in the file size of a program. The
documentation that comes with the C library describes this in more
detail, as it is too complicated to explain here in one or two
lines.</para></sect4>

<sect4><title>libcrypt, libcrypt_p</title>
<para>libcrypt is the cryptography library.</para></sect4>

<sect4><title>libdl, libdl_p</title>
<para>libdl is the dynamic linking interface library.</para></sect4>

<sect4><title>libg</title>
<para>libg is a runtime library for g++.</para></sect4>

<sect4><title>libieee</title>
<para>libieee is the IEEE floating point library.</para></sect4>

<sect4><title>libm, libm_p</title>
<para>libm is the mathematical library.</para></sect4>

<sect4><title>libmcheck</title>
<para>libmcheck contains code run at boot.</para></sect4>

<sect4><title>libmemusage</title>
<para>libmemusage is used by memusage to help collect information about the
memory usage of a program.</para></sect4>

<sect4><title>libnsl, libnsl_p</title>
<para>libnsl is the network services library.</para></sect4>

<sect4><title>libnss_compat, libnss_dns, libnss_files, 
libnss_hesiod, libnss_nis, libnss_nisplus</title>
<para>The basic idea is to put the implementation of the different services
offered to access the databases in separate modules. This has some
advantages:</para>
<itemizedlist>
<listitem><para>contributors can add new services without adding them to
GNU C library,</para></listitem>
<listitem><para>the modules can be updated separately,</para></listitem>
<listitem><para>the C library image is smaller.</para></listitem>
</itemizedlist></sect4>

<sect4><title>libpcprofile</title>
<para>Code used by the kernel to track CPU time spent in functions, source
code lines, and instructions.</para></sect4>

<sect4><title>libpthread, libpthread_p</title>
<para>The POSIX threads library.</para></sect4>

<sect4><title>libresolv, libresolv_p</title>
<para>Functions in this library provide for creating, sending, and
interpreting packets to the Internet domain name servers.</para></sect4>

<sect4><title>librpcsvc, librpcsvc_p</title>
<para>Functions in this library provide miscellaneous RPC services.</para></sect4>

<sect4><title>librt, librt_p</title>
<para>Functions in this library provide most of the interfaces specified by
the POSIX.1b Realtime Extension.</para></sect4>

<sect4><title>libthread_db</title>
<para>Functions is this library are useful for building debuggers for
multi-threaded programs.</para></sect4>

<sect4><title>libutil, libutil_p</title>
<para>Contains code for "standard" functions used in many different Unix
utilities.</para></sect4>

</sect3>

</sect2>