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#
# For a description of the syntax of this configuration file,
# see extra/config/Kconfig-language.txt
#
config HAVE_DOT_CONFIG
bool
default y
menu "General Library Settings"
config DOPIC
bool "Generate Position Independent Code (PIC)"
default y
depends !HAVE_NO_PIC
help
If you wish to build uClibc with support for shared libraries then
answer Y here. If you only want to build uClibc as a static library,
then answer N.
config HAVE_SHARED
bool "Enable support for shared libraries"
depends on DOPIC
default y
help
If you wish to build uClibc with support for shared libraries then
answer Y here. If you only want to build uClibc as a static library,
then answer N.
config ADD_LIBGCC_FUNCTIONS
bool "Add unresolved libgcc symbols to uClibc"
depends on HAVE_SHARED
default n
help
If you answer Y here, all unresolved functions provided by the libgcc
library that are used by uClibc will be added directly into the
uClibc library. If your gcc compiler only provides a static libgcc
library, then enabling this option can reduce the size of your
binaries by preventing these functions from being staticly linked
into every binary. If you have compiled uClibc as PIC code, one
potential size effect of this option is that you may end up adding
non-PIC libgcc code into your shared uClibc library, resulting in a
non shareable text segment (thereby wasting a bunch of ram). If your
compiler supports a shared libgcc library, you should certainly leave
this option disabled. Regardless, the safest answer is N.
config BUILD_UCLIBC_LDSO
bool "Compile native shared library loader"
depends on HAVE_SHARED
default y
help
uClibc has a native shared library loader for some architectures.
If you answer Y here, the uClibc native shared library loader will
be built for your target architecture. If this option is available,
to you, then you almost certainly want to answer Y.
config FORCE_SHAREABLE_TEXT_SEGMENTS
bool "Only load shared libraries which can share their text segment"
depends on BUILD_UCLIBC_LDSO && UCLIBC_COMPLETELY_PIC && !ADD_LIBGCC_SYMBOLS
default n
help
If you answer Y here, the uClibc native shared library loader will
only load shared libraries, which do not need to modify any non-writable
segments. These libraries haven't set the DT_TEXTREL tag in the dynamic
section (==> objdump). So all your libraries must be compiled with
-fPIC or -fpic, and all assembler function must be written as position
independent code (PIC).
Enabling this option will makes uClibc's shared library loader a
little bit smaller and guarantee that no memory will be wasted by badly
coded shared libraries.
config LDSO_LDD_SUPPORT
bool "Native shared library loader 'ldd' support"
depends on BUILD_UCLIBC_LDSO
default y
help
Enable this to enable all the code needed to support traditional ldd,
which executes the shared library loader to resolve all dependencies
and then provide a list of shared libraries that are required for an
application to function. Disabling this option will makes uClibc's
shared library loader a little bit smaller. Most people will answer Y.
config UCLIBC_CTOR_DTOR
bool "Support global constructors and destructors"
default y
help
If you wish to build uClibc with support for global constructor
(ctor) and global destructor (dtor) support, then answer Y here.
When ctor/dtor support is enabled, binaries linked with uClibc must
also be linked with crtbegin.o and crtend.o which are provided by gcc
(the "*startfile:" and "*endfile:" settings in your gcc specs file
may need to be adjusted to include these files). This support will
also add a small amount of additional size to each binary compiled vs
uClibc. If you will be using uClibc with C++, or if you need the gcc
__attribute__((constructor)) and __attribute__((destructor)) to work,
then you definitely want to answer Y here. If you don't need ctors
or dtors and want your binaries to be as small as possible, then
answer N.
config UCLIBC_PROFILING
bool "Support gprof profiling"
default y
help
If you wish to build uClibc with support for application profiling
using the gprof tool, then you should enable this feature. Then in
addition to building uClibc with profiling support, you will also
need to recompile all your shared libraries with the profiling
enabled version of uClibc. To add profiling support to your
applications, you must compile things using the gcc options
"-fprofile-arcs -pg". Then when you run your applications, a
gmon.out file will be generated which can then be analyzed by
'gprof'.
These exist a number of less invasive alternatives that do not
require your to specially instrument your application, and recompile
and relink everything.
Many people have had good results using the combination of Valgrind
to generate profiling information and KCachegrind for analysis:
http://developer.kde.org/~sewardj/
http://kcachegrind.sourceforge.net/
The OProfile system-wide profiler is another alternative:
http://oprofile.sourceforge.net/
Prospect is another alternative based on OProfile:
http://prospect.sourceforge.net/
And the Linux Trace Toolkit (LTT) is also a fine tool:
http://www.opersys.com/LTT/
If none of these tools do what you need, you can of course enable
this option, rebuild everything, and use 'gprof'. There is both a
size and performance penelty to profiling your applications this way,
so most people should answer N.
config UCLIBC_HAS_THREADS
bool "POSIX Threading Support"
default y
help
If you want to compile uClibc with pthread support, then answer Y.
This will increase the size of uClibc by adding a bunch of locking
to critical data structures, and adding extra code to ensure that
functions are properly reentrant.
If your applications require pthreads, answer Y.
config UCLIBC_HAS_LFS
bool "Large File Support"
default y
help
If you wish to build uClibc with support for accessing large files
(i.e. files greater then 2 GiB) then answer Y. Do not enable this
if you are using an older Linux kernel (2.0.x) that lacks large file
support. Enabling this option will increase the size of uClibc.
choice
prompt "Malloc Implementation"
default "malloc-930716"
help
"malloc" use mmap for all allocations and so works very well on MMU-less
systems that do not support the brk() system call. It is pretty smart
about reusing already allocated memory, and minimizing memory wastage.
"malloc-930716" is derived from libc-5.3.12 and uses the brk() system call
for all memory allocations. This makes it very fast. It is also pretty
smart about reusing already allocated memory, and minimizing memory wastage.
Because this uses brk() it will not work on uClinux MMU-less systems.
If unsure, answer "malloc".
config MALLOC
bool "malloc"
config MALLOC_930716
bool "malloc-930716"
depends on UCLIBC_HAS_MMU
endchoice
config UCLIBC_DYNAMIC_ATEXIT
bool "Dynamic atexit() Support"
default y
help
When this option is enabled, uClibc will support an infinite number,
of atexit() and on_exit() functions, limited only by your available
memory. This can be important when uClibc is used with C++, since
global destructors are implemented via atexit(), and it is quite
possible to exceed the default number when this option is disabled.
Enabling this option adds a few bytes, and more significantly makes
atexit and on_exit depend on malloc, which can be bad when compiling
static executables.
Unless you use uClibc with C++, you should probably answer N.
config HAS_SHADOW
bool "Shadow Password Support"
default y
help
Answer N if you do not need shadow password support.
Most people will answer Y.
config UCLIBC_HAS_REGEX
bool "Regular Expression Support"
default y
help
POSIX regular expression code is really big -- 27k all by itself.
If you don't use regular expressions, turn this off and save space.
Of course, if you only staticly link, leave this on, since it will
only be included in your apps if you use regular expressions.
config UNIX98PTY_ONLY
bool "Support only Unix 98 PTYs"
default y
help
If you want to support only Unix 98 PTYs enable this. Some older
applications may need this disabled. For most current programs,
you can generally answer Y.
config ASSUME_DEVPTS
bool "Assume that /dev/pts is a devpts or devfs file system"
default y
help
Enable this if /dev/pts is on a devpts or devfs filesystem. Both
these filesystems automatically manage permissions on the /dev/pts
devices. You may need to mount your devpts or devfs filesystem on
/dev/pts for this to work.
Most people should answer Y.
endmenu
menu "Networking Support"
config UCLIBC_HAS_IPV6
bool "IP version 6 Support"
default n
help
If you want to include support for the next version of the Internet
Protocol (IP version 6) then answer Y.
Most people should answer N.
config UCLIBC_HAS_RPC
bool "Remote Procedure Call (RPC) support"
default n
help
If you want to include RPC support, enable this. RPC is rarely used
for anything except for the NFS filesystem. Unless you plan to use NFS,
you can probably leave this set to N and save some space. If you need
to use NFS then you should answer Y.
config UCLIBC_HAS_FULL_RPC
bool "Full RPC support"
depends on UCLIBC_HAS_RPC
default y if !HAVE_SHARED
help
Normally we enable just enough RPC support for things like rshd and
nfs mounts to work. If you find you need the rest of the RPC stuff,
then enable this option. Most people can safely answer N.
endmenu
menu "String and Stdio Support"
config UCLIBC_HAS_WCHAR
bool "Wide Character Support"
default n
help
Answer Y to enable wide character support. This will make uClibc
much larger.
Most people will answer N.
config UCLIBC_HAS_LOCALE
bool "Locale Support (experimental/incomplete)"
depends on UCLIBC_HAS_WCHAR
default n
help
Answer Y to enable locale support. This will make uClibc much
bigger. uClibc's locale support is still under development, and
should be finished in the next several weeks (November 2002).
Most people will wisely answer N.
config USE_OLD_VFPRINTF
bool "Use the old vfprintf implementation"
default n
help
Set to true to use the old vfprintf instead of the new. This is roughly
C89 compliant, but doesn't deal with qualifiers on %n and doesn't deal with
%h correctly or %hh at all on the integer conversions. But on i386 it is
over 1.5k smaller than the new code. Of course, the new code fixes the
above mentioned deficiencies and adds custom specifier support similar to
glibc, as well as handling positional args. This will be rewritten at some
point to bring it to full C89 standards compliance.
Most people will answer N.
endmenu
menu "Library Installation Options"
config SHARED_LIB_LOADER_PATH
string "Shared library loader path"
depends on BUILD_UCLIBC_LDSO
default "$(DEVEL_PREFIX)/lib"
help
When using shared libraries, this path is the location where the
shared library will be invoked. This value will be compiled into
every binary compiled with uClibc.
BIG FAT WARNING:
If you do not have a shared library loader with the correct name
sitting in the directory this points to, your binaries will not
run.
config SYSTEM_LDSO
string "System shared library loader"
depends on HAVE_SHARED && !BUILD_UCLIBC_LDSO
default "/lib/ld-linux.so.2"
help
If you are using shared libraries, but do not want/have a native
uClibc shared library loader, please specify the name of your
target system's shared library loader here...
BIG FAT WARNING:
If you do not have a shared library loader with the correct name
sitting in the directory this points to, your binaries will not
run.
config DEVEL_PREFIX
string "uClibc development environment directory"
default "/usr/$(TARGET_ARCH)-linux-uclibc"
help
DEVEL_PREFIX is the directory into which the uClibc development
environment will be installed. The result will look something
like the following:
$(DEVEL_PREFIX)/
lib/ <contains all runtime and static libs>
include/ <Where all the header files go>
This value is used by the 'make install' Makefile target. Since this
directory is compiled into the uclibc cross compiler spoofer, you
have to recompile uClibc if you change this value...
config SYSTEM_DEVEL_PREFIX
string "uClibc development environment system directory"
default "$(DEVEL_PREFIX)"
help
SYSTEM_DEVEL_PREFIX is the directory prefix used when installing
bin/arch-uclibc-gcc, bin/arch-uclibc-ld, etc. This is only used by
the 'make install' target, and is not compiled into anything. This
defaults to $(DEVEL_PREFIX)/usr, but makers of .rpms and .debs will
want to set this to "/usr" instead.
config DEVEL_TOOL_PREFIX
string "uClibc development environment tool directory"
default "$(DEVEL_PREFIX)/usr"
help
DEVEL_TOOL_PREFIX is the directory prefix used when installing
bin/gcc, bin/ld, etc. This is only used by the 'make install'
target, and is not compiled into anything. This defaults to
$(DEVEL_PREFIX)/usr, but makers of .rpms and .debs may want to
set this to something else.
endmenu
menu "uClibc hacking options"
config DODEBUG
bool "Build uClibc with debugging symbols"
default n
help
Say Y here if you wish to compile uClibc with debugging symbols.
This will allow you to use a debugger to examine uClibc internals
while applications are running. This increases the size of the
library considerably and should only be used when doing development.
If you are doing development and want to debug uClibc, answer Y.
Otherwise, answer N.
config DOASSERTS
bool "Build uClibc with run-time assertion testing"
default n
help
Say Y here to include runtime assertion tests.
This enables runtime assertion testing in some code, which can
increase the size of the library and incur runtime overhead.
If you say N, then this testing will be disabled.
config SUPPORT_LD_DEBUG
bool "Build the shared library loader with debugging support"
depends on BUILD_UCLIBC_LDSO
default n
help
Answer Y here to enable all the extra code needed to debug the uClibc
native shared library loader. The level of debugging noise that is
generated depends on the LD_DEBUG environment variable... Just set
LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
debug your application. Diagnostic messages will then be printed to
the stderr.
For now these debugging tokens are available:
detail provide more information for some options
move display copy processing
symbols display symbol table processing
reloc display relocation processing; detail shows the relocation patch
nofixups never fixes up jump relocations
bindings displays the resolve processing (function calls); detail shows the relocation patch
all Enable everything!
The additional environment variable:
LD_DEBUG_OUTPUT=file
redirects the diagnostics to an output file created using
the specified name and the process id as a suffix.
An excellent start is simply:
$ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
or to log everything to a file named 'logfile', try this
$ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
If you are doing development and want to debug uClibc's shared library
loader, answer Y. Mere mortals answer N.
config SUPPORT_LD_DEBUG_EARLY
bool "Build the shared library loader with early debugging support"
depends on BUILD_UCLIBC_LDSO
default n
help
Answer Y here to if you find the uClibc shared library loader is
crashing or otherwise not working very early on. This is typical
only when starting a new port when you haven't figured out how to
properly get the values for argc, argv, environ, etc. This method
allows a degree of visibility into the very early shared library
loader initialization process. If you are doing development and want
to debug the uClibc shared library loader early initialization,
answer Y. Mere mortals answer N.
config UCLIBC_MALLOC_DEBUGGING
bool "Build malloc with debugging support"
depends MALLOC
default n
help
Answer Y here to compile extra debugging support code into malloc.
Malloc debugging output may then be enabled at runtime using
the MALLOC_DEBUG environment variable. Because this increases
the size of malloc appreciably (due to strings etc), you
should say N unless you need to debug a malloc problem.
endmenu
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