(libtool14.info.gz) libtool script contents
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13.4 `libtool' script contents
==============================
Since version 1.4, the `libtool' script is generated by `configure'
( Configuring). In earlier versions, `configure' achieved this
by calling a helper script called `ltconfig'. From libtool version 0.7
to 1.0, this script simply set shell variables, then sourced the
libtool backend, `ltmain.sh'. `ltconfig' from libtool version 1.1
through 1.3 inlined the contents of `ltmain.sh' into the generated
`libtool', which improved performance on many systems. The tests that
`ltconfig' used to perform are now kept in `libtool.m4' where thay can
be written using Autoconf. This has the runtime performance benefits
of inlined `ltmain.sh', _and_ improves the build time a little while
considerably easing the amount of raw shell code that used to need
maintaining.
The convention used for naming variables which hold shell commands
for delayed evaluation, is to use the suffix `_cmd' where a single line
of valid shell script is needed, and the suffix `_cmds' where multiple
lines of shell script *may* be delayed for later evaluation. By
convention, `_cmds' variables delimit the evaluation units with the `~'
character where necessary.
Here is a listing of each of the configuration variables, and how
they are used within `ltmain.sh' ( Configuring):
-- Variable: AR
The name of the system library archiver.
-- Variable: CC
The name of the C compiler used to configure libtool.
-- Variable: LD
The name of the linker that libtool should use internally for
reloadable linking and possibly shared libraries.
-- Variable: NM
The name of a BSD-compatible `nm' program, which produces listings
of global symbols in one the following formats:
ADDRESS C GLOBAL-VARIABLE-NAME
ADDRESS D GLOBAL-VARIABLE-NAME
ADDRESS T GLOBAL-FUNCTION-NAME
-- Variable: RANLIB
Set to the name of the ranlib program, if any.
-- Variable: allow_undefined_flag
The flag that is used by `archive_cmds' in order to declare that
there will be unresolved symbols in the resulting shared library.
Empty, if no such flag is required. Set to `unsupported' if there
is no way to generate a shared library with references to symbols
that aren't defined in that library.
-- Variable: always_export_symbols
Whether libtool should automatically generate a list of exported
symbols using EXPORT_SYMBOLS_CMDS before linking an archive. Set
to `yes' or `no'. Default is `no'.
-- Variable: archive_cmds
-- Variable: archive_expsym_cmds
-- Variable: old_archive_cmds
Commands used to create shared libraries, shared libraries with
`-export-symbols' and static libraries, respectively.
-- Variable: old_archive_from_new_cmds
If the shared library depends on a static library,
`old_archive_from_new_cmds' contains the commands used to create
that static library. If this variable is not empty,
`old_archive_cmds' is not used.
-- Variable: old_archive_from_expsyms_cmds
If a static library must be created from the export symbol list in
order to correctly link with a shared library,
`old_archive_from_expsyms_cmds' contains the commands needed to
create that static library. When these commands are executed, the
variable SONAME contains the name of the shared library in
question, and the $OBJDIR/$NEWLIB contains the path of the static
library these commands should build. After executing these
commands, libtool will proceed to link against $OBJDIR/$NEWLIB
instead of SONAME.
-- Variable: build_libtool_libs
Whether libtool should build shared libraries on this system. Set
to `yes' or `no'.
-- Variable: build_old_libs
Whether libtool should build static libraries on this system. Set
to `yes' or `no'.
-- Variable: compiler_c_o
Whether the compiler supports the `-c' and `-o' options
simultaneously. Set to `yes' or `no'.
-- Variable: compiler_o_lo
Whether the compiler supports compiling directly to a ".lo" file,
i.e whether object files do not have to have the suffix ".o". Set
to `yes' or `no'.
-- Variable: dlopen_support
Whether `dlopen' is supported on the platform. Set to `yes' or
`no'.
-- Variable: dlopen_self
Whether it is possible to `dlopen' the executable itself. Set to
`yes' or `no'.
-- Variable: dlopen_self_static
Whether it is possible to `dlopen' the executable itself, when it
is linked statically (`-all-static'). Set to `yes' or `no'.
-- Variable: echo
An `echo' program which does not interpret backslashes as an
escape character.
-- Variable: exclude_expsyms
List of symbols that should not be listed in the preloaded symbols.
-- Variable: export_dynamic_flag_spec
Compiler link flag that allows a dlopened shared library to
reference symbols that are defined in the program.
-- Variable: export_symbols_cmds
Commands to extract exported symbols from LIBOBJS to the file
EXPORT_SYMBOLS.
-- Variable: extract_expsyms_cmds
Commands to extract the exported symbols list from a shared
library. These commands are executed if there is no file
$OBJDIR/$SONAME-DEF, and should write the names of the exported
symbols to that file, for the use of
`old_archive_from_expsyms_cmds'.
-- Variable: fast_install
Determines whether libtool will privilege the installer or the
developer. The assumption is that installers will seldom run
programs in the build tree, and the developer will seldom install.
This is only meaningful on platforms in which
SHLIBPATH_OVERRIDES_RUNPATH is not `yes', so FAST_INSTALL will be
set to `needless' in this case. If FAST_INSTALL set to `yes',
libtool will create programs that search for installed libraries,
and, if a program is run in the build tree, a new copy will be
linked on-demand to use the yet-to-be-installed libraries. If set
to `no', libtool will create programs that use the
yet-to-be-installed libraries, and will link a new copy of the
program at install time. The default value is `yes' or
`needless', depending on platform and configuration flags, and it
can be turned from `yes' to `no' with the configure flag
`--disable-fast-install'.
-- Variable: finish_cmds
Commands to tell the dynamic linker how to find shared libraries
in a specific directory.
-- Variable: finish_eval
Same as FINISH_CMDS, except the commands are not displayed.
-- Variable: fix_srcfile_path
Expression to fix the shell variable $srcfile for the compiler.
-- Variable: global_symbol_pipe
A pipeline that takes the output of NM, and produces a listing of
raw symbols followed by their C names. For example:
$ eval "$NM progname | $global_symbol_pipe"
D SYMBOL1 C-SYMBOL1
T SYMBOL2 C-SYMBOL2
C SYMBOL3 C-SYMBOL3
...
$
The first column contains the symbol type (used to tell data from
code on some platforms), but its meaning is system dependent.
-- Variable: global_symbol_to_cdecl
A pipeline that translates the output of GLOBAL_SYMBOL_PIPE into
proper C declarations. On platforms whose linkers differentiate
code from data, such as HP/UX, data symbols will be declared as
such, and code symbols will be declared as functions. On
platforms that don't care, everything is assumed to be data.
-- Variable: hardcode_action
Either `immediate' or `relink', depending on whether shared
library paths can be hardcoded into executables before they are
installed, or if they need to be relinked.
-- Variable: hardcode_direct
Set to `yes' or `no', depending on whether the linker hardcodes
directories if a library is directly specified on the command line
(such as `DIR/libNAME.a') when HARDCODE_LIBDIR_FLAG_SPEC is
specified.
-- Variable: hardcode_into_libs
Whether the platform supports hardcoding of run-paths into
libraries. If enabled, linking of programs will be much simpler
but libraries will need to be relinked during installation. Set
to `yes' or `no'.
-- Variable: hardcode_libdir_flag_spec
Flag to hardcode a LIBDIR variable into a binary, so that the
dynamic linker searches LIBDIR for shared libraries at runtime.
If it is empty, libtool will try to use some other hardcoding
mechanism.
-- Variable: hardcode_libdir_separator
If the compiler only accepts a single HARDCODE_LIBDIR_FLAG, then
this variable contains the string that should separate multiple
arguments to that flag.
-- Variable: hardcode_minus_L
Set to `yes' or `no', depending on whether the linker hardcodes
directories specified by `-L' flags into the resulting executable
when HARDCODE_LIBDIR_FLAG_SPEC is specified.
-- Variable: hardcode_shlibpath_var
Set to `yes' or `no', depending on whether the linker hardcodes
directories by writing the contents of `$shlibpath_var' into the
resulting executable when HARDCODE_LIBDIR_FLAG_SPEC is specified.
Set to `unsupported' if directories specified by `$shlibpath_var'
are searched at run time, but not at link time.
-- Variable: host
-- Variable: host_alias
For information purposes, set to the specified and canonical names
of the system that libtool was configured for.
-- Variable: include_expsyms
List of symbols that must always be exported when using
EXPORT_SYMBOLS.
-- Variable: libext
The standard old archive suffix (normally "a").
-- Variable: libname_spec
The format of a library name prefix. On all Unix systems, static
libraries are called `libNAME.a', but on some systems (such as
OS/2 or MS-DOS), the library is just called `NAME.a'.
-- Variable: library_names_spec
A list of shared library names. The first is the name of the file,
the rest are symbolic links to the file. The name in the list is
the file name that the linker finds when given `-lNAME'.
-- Variable: link_all_deplibs
Whether libtool must link a program against all its dependency
libraries. Set to `yes' or `no'. Default is `unknown', which is
a synonym for `yes'.
-- Variable: link_static_flag
Linker flag (passed through the C compiler) used to prevent dynamic
linking.
-- Variable: need_lib_prefix
Whether libtool should automatically prefix module names with
'lib'. Set to `yes' or `no'. By default, it is `unknown', which
means the same as `yes', but documents that we are not really sure
about it. `yes' means that it is possible both to `dlopen' and to
link against a library without 'lib' prefix, i.e. it requires
HARDCODE_DIRECT to be `yes'.
-- Variable: need_version
Whether versioning is required for libraries, i.e. whether the
dynamic linker requires a version suffix for all libraries. Set
to `yes' or `no'. By default, it is `unknown', which means the
same as `yes', but documents that we are not really sure about it.
-- Variable: need_locks
Whether files must be locked to prevent conflicts when compiling
simultaneously. Set to `yes' or `no'.
-- Variable: no_builtin_flag
Compiler flag to disable builtin functions that conflict with
declaring external global symbols as `char'.
-- Variable: no_undefined_flag
The flag that is used by `archive_cmds' in order to declare that
there will be no unresolved symbols in the resulting shared
library. Empty, if no such flag is required.
-- Variable: objdir
The name of the directory that contains temporary libtool files.
-- Variable: objext
The standard object file suffix (normally "o").
-- Variable: pic_flag
Any additional compiler flags for building library object files.
-- Variable: postinstall_cmds
-- Variable: old_postinstall_cmds
Commands run after installing a shared or static library,
respectively.
-- Variable: postuninstall_cmds
-- Variable: old_postuninstall_cmds
Commands run after uninstalling a shared or static library,
respectively.
-- Variable: reload_cmds
-- Variable: reload_flag
Commands to create a reloadable object.
-- Variable: runpath_var
The environment variable that tells the linker which directories to
hardcode in the resulting executable.
-- Variable: shlibpath_overrides_runpath
Indicates whether it is possible to override the hard-coded library
search path of a program with an environment variable. If this is
set to no, libtool may have to create two copies of a program in
the build tree, one to be installed and one to be run in the build
tree only. When each of these copies is created depends on the
value of `fast_install'. The default value is `unknown', which is
equivalent to `no'.
-- Variable: shlibpath_var
The environment variable that tells the dynamic linker where to
find shared libraries.
-- Variable: soname_spec
The name coded into shared libraries, if different from the real
name of the file.
-- Variable: striplib
-- Variable: old_striplib
Command to strip a shared (`striplib') or static (`old_striplib')
library, respectively. If these variables are empty, the strip
flag in the install mode will be ignored for libraries (
Install mode).
-- Variable: sys_lib_dlsearch_path_spec
Expression to get the run-time system library search path.
Directories that appear in this list are never hard-coded into
executables.
-- Variable: sys_lib_search_path_spec
Expression to get the compile-time system library search path.
This variable is used by libtool when it has to test whether a
certain library is shared or static. The directories listed in
SHLIBPATH_VAR are automatically appended to this list, every time
libtool runs (i.e., not at configuration time), because some
linkers use this variable to extend the library search path.
Linker switches such as `-L' also augment the search path.
-- Variable: thread_safe_flag_spec
Linker flag (passed through the C compiler) used to generate
thread-safe libraries.
-- Variable: version_type
The library version numbering type. One of `libtool',
`freebsd-aout', `freebsd-elf', `irix', `linux', `osf', `sunos',
`windows', or `none'.
-- Variable: whole_archive_flag_spec
Compiler flag to generate shared objects from convenience archives.
-- Variable: wl
The C compiler flag that allows libtool to pass a flag directly to
the linker. Used as: `${wl}SOME-FLAG'.
Variables ending in `_cmds' or `_eval' contain a `~'-separated list
of commands that are `eval'ed one after another. If any of the
commands return a nonzero exit status, libtool generally exits with an
error message.
Variables ending in `_spec' are `eval'ed before being used by
libtool.
Info Catalog
(libtool14.info.gz) Platform quirks
(libtool14.info.gz) Maintaining
(libtool14.info.gz) Cheap tricks
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