Manual page for LIBTOOL(1)
libtool - create libraries
ranlib - add or update the table of contents of archive libraries
SYNOPSIS
libtool
-static
-o output
[
-sac
]
[
-
]
[
-arch_only arch_type
]
file...
[-filelist listfile[,dirname]]
libtool
-dynamic
-o output
[
-install_name name
]
[
-compatiblity_version number
]
[
-current_version number
]
[
link editor flags
]
[
-v
]
[
-
]
[
-arch_only arch_type
]
file...
[-filelist listfile[,dirname]]
ranlib
[
-sact
]
[
-
]
archive...
DESCRIPTION
The
libtool
command takes the specified input object files and creates a library for
use with the link editor,
ld.1
The library's name is specified by
output
(the argument
to the
-o
flag). The input object files may be
in any correct format that contains object files (``fat'' files, archives, object
files).
Libtool
will not put any non-object input file into the output library
(unlike
ranlib,
which allows this in the archives it operates on).
When producing a ``fat'' file from objects of the same CPU type and differing
CPU subtypes,
libtool
and
ranlib
create at most one library for
each CPU type, rather than a separate library in a fat file for each of the
unique pairings of
CPU type and CPU subtype. Thus, the resulting CPU subtype for each library
is the _ALL
CPU subtype for that CPU type. This strategy strongly encourages the implementor
of a library to create one library that
chooses optimum code to run at run time, rather than at link time.
Libtool
can create either dynamically linked shared libraries, with
-dynamic,
or statically linked (archive) libraries, with
-static.
DYNAMICALLY LINKED SHARED LIBRARIES
Dynamically linked libraries, unlike statically linked libraries, are Mach-O format
files and not
ar.5
format files.
Dynamically linked libraries have two restrictions: No symbol may be defined
in more than one object file and no common symbol can be used.
To maximize sharing of a dynamically linked shared library the objects should
be compiled with the
-dynamic
flag of
cc.1
to produce indirect undefined references and possition-independent code.
To build a dynamically linked library,
libtool,
runs the link editor,
ld.1
with
-dylib
once for each architecutre present in the input objects and then
lipo.1
to create a fat file if needed.
ARCHIVE (or statically linked) LIBRARIES
Libtool
with
-static
is intended to replace
ar.5
and
ranlib.
For backward compatibility,
ranlib
is still available, and it
supports fat files.
Ranlib
adds or updates the table of contents to each
archive
so it can be linked by the link editor,
ld.1
The table of contents is an archive member at the beginning of the archive that
indicates which symbols are defined in which library members.
Because
ranlib
rewrites the archive, sufficient temporary file space must
be available in the file system that contains the current directory.
Ranlib
takes all correct forms of libraries (fat files containing archives, and simple
archives) and updates the table of contents for all archives in the file.
Ranlib
also takes one common incorrect form of archive, an archive whose members are
fat object files, adding or updating the table of contents and producing the
library in correct form (a fat file containing multiple archives).
The archive member name for a table of contents begins with
``__.SYMDEF''.
Currently, there are two types of table of contents produced by
libtool -static
and
ranlib
and understood by the link editor,
ld.1
These are explained below, under the
-s
and
-a
options.
OPTIONS
The following options pertain to
libtool
only.
- -static
-
Produce a statically linked (archive) library from the input files.
This is the default.
- -dynamic
-
Produce a dynamically linked shared library from the input files.
- -install_name name
-
For a dynamic shared library this specifies the file
name
the library will be installed in for programs that use it. If this is not
specified the name specified by the
-o output
option will be used.
- -compatibility_version number
-
For a dynamic shared library this specifies the compatibility version number
of the library. When a library is used the compatibility version is checked
and if the user's version is greater that the library's version, an error message is printed and the using program exits.
The format of
number
is
X[.Y[.Z]]
where
X
must be a positive non-zero number less than or equal to 65535, and
.Y
and
.Z
are optional and if present must be a positive non-zero numbers less than or
equal to 255.
If this is not specified then it has a
value of 0 and no checking is done when the library is used.
- -current_version number
-
For dynamic shared library files this specifies the current version number
of the library. The program using the library can obtain the
current version of the library programmatically to determine exactly
which version of the library it is using.
The format of
number
is
X[.Y[.Z]]
where
X
must be a positive non-zero number less than or equal to 65535, and
.Y
and
.Z
are optional and if present must be a positive non-zero numbers less than or
equal to 255.
If this is not specified then it has a
value of 0.
- link editor flags
-
For a dynamic shared library the following
ld.1
flags are accepted and passed through:
-lx,
-Ldir,
-ysym,
-seg1addr,
-segprot,
-segalign,
-sectcreate,
-sectorder,
-sectorder_detail,
-sectalign,
-undefined,
-read_only_relocs,
-prebind,
-framework,
-F.
See the
ld.1
man page for details on these flags.
The flag
-image_base
is a synonym for
-seg1addr.
- -v
-
Verbose mode, which prints the
ld.1
commands and
lipo.1
commands executed.
- -filelist listfile[,dirname]
-
The
listfile
contains a list of file names and is an alternative way of specifiying file
names on the command line. The file names are listed one per line separated
only by newlines (spaces and tabs are assumed to be part of the file name).
If the optional directory name,
dirname
is specified then it is prepended to each name in the list file.
- -arch_only arch_type
-
This option causes libtool to build a library only for the specified
arch_type
and ignores all other architectures in the input files.
The following options pertain to the table of contents for an archive library,
and apply to both
libtool -static
and
ranlib:
- -s
-
Produce the preferred type of table of contents, which results in faster link
editing when linking with the archive. The order of the table of contents is
sorted by symbol name. The library member name of this type of table of
contents is
``__.SYMDEF SORTED''.
This type of table of contents can only be produced when the library does not
have multiple members that define the same symbol. This is the default.
- -a
-
Produce the original type of table of contents, whose order is based on the order
of the members in the archive. The library member name of this type of table of
contents is
``__.SYMDEF''.
This type of table of contents must be used when the library has
multiple members that define the same symbol.
- -c
-
Include common symbols as definitions with respect to the table of contents.
This is seldom the intended behavior for linking from a library,
as it forces the linking of a library member just because it uses an
uninitialized global that is undefined at that point in the linking. This option is
included only because this was the original behavior of
ranlib.
This option is not the default.
For compatibility, the following
ranlib
option is accepted (but ignored):
- -t
-
This option used to request that
ranlib
only ``touch'' the archives instead of modifying them.
The option is now ignored, and the table of contents is rebuilt.
One other option applies to both
libtool
and
ranlib:
- -
-
Treat all remaining arguments as names of files (or archives) and not as
options.
SEE ALSO
ld(1), ar(1), otool(1), make(1), redo_prebinding(1), ar(5)
BUGS
The way libraries used to be created, errors were possible if the library
was modified with
ar.1
and the table of contents was not updated by rerunning
ranlib.1
Thus the link editor,
ld,
warns when the modification date of a library is more recent than the
creation date of its table of contents. Unfortunately, this means that
you get the warning even if you only copy the library.
Created by unroff & hp-tools.
© somebody (See intro for details). All Rights Reserved.
Last modified 11/5/97
