静态库的生成方法

静态库的生成方法


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ar
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ar crv $@ a.o b.o c.o 
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AR(1)                                         GNU Development Tools                                        AR(1)



NAME
       ar - create, modify, and extract from archives

SYNOPSIS
       ar [-X32_64] [-]p[mod [relpos] [count]] archive [member...]

DESCRIPTION
       The  GNU ar program creates, modifies, and extracts from archives.  An archive is a single file holding a
       collection of other files in a structure that makes it possible to retrieve the original individual files
       (called members of the archive).

       The  original  files'  contents,  mode  (permissions),  timestamp,  owner, and group are preserved in the
       archive, and can be restored on extraction.

       GNU ar can maintain archives whose members have names of any length; however, depending on how ar is con-
       figured  on your system, a limit on member-name length may be imposed for compatibility with archive for-
       mats maintained with other tools.  If it exists, the limit is often 15  characters  (typical  of  formats
       related to a.out) or 16 characters (typical of formats related to coff).

       ar  is considered a binary utility because archives of this sort are most often used as libraries holding
       commonly needed subroutines.

       ar creates an index to the symbols defined in relocatable object modules in the archive when you  specify
       the  modifier  s.   Once  created, this index is updated in the archive whenever ar makes a change to its
       contents (save for the q update operation).  An archive with such an  index  speeds  up  linking  to  the
       library,  and  allows routines in the library to call each other without regard to their placement in the
       archive.

       You may use nm -s or nm --print-armap to list this index table.  If an archive lacks the  table,  another
       form of ar called ranlib can be used to add just the table.

       GNU ar can optionally create a thin archive, which contains a symbol index and references to the original
       copies of the member files of the archives.  Such an archive is useful for  building  libraries  for  use
       within  a  local  build,  where the relocatable objects are expected to remain available, and copying the
       contents of each object would only waste time and space.  Thin  archives  are  also  flattened,  so  that
       adding  one  or more archives to a thin archive will add the elements of the nested archive individually.
       The paths to the elements of the archive are stored relative to the archive itself.

       GNU ar is designed to be compatible with two different facilities.  You can control  its  activity  using
       command-line  options,  like the different varieties of ar on Unix systems; or, if you specify the single
       command-line option -M, you can control it with a script  supplied  via  standard  input,  like  the  MRI
       "librarian" program.
OPTIONS
       GNU  ar allows you to mix the operation code p and modifier flags mod in any order, within the first com-
       mand-line argument.

       If you wish, you may begin the first command-line argument with a dash.

       The p keyletter specifies what operation to execute; it may be any of the following, but you must specify
       only one of them:

       d   Delete  modules  from  the  archive.   Specify  the  names of modules to be deleted as member...; the
           archive is untouched if you specify no files to delete.

           If you specify the v modifier, ar lists each module as it is deleted.

       m   Use this operation to move members in an archive.

           The ordering of members in an archive can make a difference in how  programs  are  linked  using  the
           library, if a symbol is defined in more than one member.

           If  no modifiers are used with "m", any members you name in the member arguments are moved to the end
           of the archive; you can use the a, b, or i modifiers to move them to a specified place instead.

       p   Print the specified members of the archive, to the standard output file.  If the v modifier is speci-
           fied, show the member name before copying its contents to standard output.

           If you specify no member arguments, all the files in the archive are printed.

       q   Quick  append;  Historically,  add  the  files  member... to the end of archive, without checking for
           replacement.

           The modifiers a, b, and i do not affect this operation; new members are always placed at the  end  of
           the archive.

           The modifier v makes ar list each file as it is appended.

           Since  the point of this operation is speed, the archive's symbol table index is not updated, even if
           it already existed; you can use ar s or ranlib explicitly to update the symbol table index.

           However, too many different systems assume quick append rebuilds the index, so GNU ar implements q as
           a synonym for r.

       r   Insert the files member... into archive (with replacement). This operation differs from q in that any
           previously existing members are deleted if their names match those being added.

           If one of the files named in member... does not exist, ar  displays  an  error  message,  and  leaves
           undisturbed any existing members of the archive matching that name.
           By  default, new members are added at the end of the file; but you may use one of the modifiers a, b,
           or i to request placement relative to some existing member.

           The modifier v used with this operation elicits a line of output for each file inserted,  along  with
           one  of  the  letters  a  or  r  to indicate whether the file was appended (no old member deleted) or
           replaced.

       t   Display a table listing the contents of archive, or those of the files listed in member...  that  are
           present  in  the  archive.  Normally only the member name is shown; if you also want to see the modes
           (permissions), timestamp, owner, group, and size, you can request that by also specifying the v modi-
           fier.

           If you do not specify a member, all files in the archive are listed.

           If  there  is  more than one file with the same name (say, fie) in an archive (say b.a), ar t b.a fie
           lists only the first instance; to see them all, you must ask for a complete listing---in our example,
           ar t b.a.

       x   Extract  members (named member) from the archive.  You can use the v modifier with this operation, to
           request that ar list each name as it extracts it.

           If you do not specify a member, all files in the archive are extracted.

           Files cannot be extracted from a thin archive.

       A number of modifiers (mod) may immediately follow the p keyletter, to specify variations  on  an  opera-
       tion's behavior:

       a   Add  new  files  after  an existing member of the archive.  If you use the modifier a, the name of an
           existing archive member must be present as the relpos argument, before the archive specification.

       b   Add new files before an existing member of the archive.  If you use the modifier b, the  name  of  an
           existing  archive  member  must  be present as the relpos argument, before the archive specification.
           (same as i).

       c   Create the archive.  The specified archive is always created if it did not exist, when you request an
           update.  But a warning is issued unless you specify in advance that you expect to create it, by using
           this modifier.

       f   Truncate names in the archive.  GNU ar will normally permit file names  of  any  length.   This  will
           cause  it to create archives which are not compatible with the native ar program on some systems.  If
           this is a concern, the f modifier may be used to  truncate  file  names  when  putting  them  in  the
           archive.
       i   Insert new files before an existing member of the archive.  If you use the modifier i, the name of an
           existing archive member must be present as the relpos argument,  before  the  archive  specification.
           (same as b).

       l   This modifier is accepted but not used.

       N   Uses  the  count  parameter.  This is used if there are multiple entries in the archive with the same
           name.  Extract or delete instance count of the given name from the archive.

       o   Preserve the original dates of members when extracting them.  If you do not  specify  this  modifier,
           files extracted from the archive are stamped with the time of extraction.

       P   Use  the  full path name when matching names in the archive.  GNU ar can not create an archive with a
           full path name (such archives are not POSIX complaint), but other archive creators can.  This  option
           will  cause  GNU  ar  to  match  file  names using a complete path name, which can be convenient when
           extracting a single file from an archive created by another tool.

       s   Write an object-file index into the archive, or update an existing one, even if no  other  change  is
           made to the archive.  You may use this modifier flag either with any operation, or alone.  Running ar
           s on an archive is equivalent to running ranlib on it.

       S   Do not generate an archive symbol table.  This can speed up  building  a  large  library  in  several
           steps.  The resulting archive can not be used with the linker.  In order to build a symbol table, you
           must omit the S modifier on the last execution of ar, or you must run ranlib on the archive.

       T   Make the specified archive a thin archive.  If it already exists and is a regular archive, the exist-
           ing members must be present in the same directory as archive.

       u   Normally,  ar r... inserts all files listed into the archive.  If you would like to insert only those
           of the files you list that are newer than existing members of the same names, use this modifier.  The
           u  modifier  is allowed only for the operation r (replace).  In particular, the combination qu is not
           allowed, since checking the timestamps would lose any speed advantage from the operation q.

       v   This modifier requests the verbose version of  an  operation.   Many  operations  display  additional
           information, such as filenames processed, when the modifier v is appended.

       V   This modifier shows the version number of ar.

       ar  ignores  an initial option spelt -X32_64, for compatibility with AIX.  The behaviour produced by this
       option is the default for GNU ar.  ar does not support any of the other -X  options;  in  particular,  it
       does not support -X32 which is the default for AIX ar.

       @file
           Read  command-line  options  from file.  The options read are inserted in place of the original @file
           option.  If file does not exist, or cannot be read, then the option will be  treated  literally,  and
           not removed.

           Options  in file are separated by whitespace.  A whitespace character may be included in an option by
           surrounding the entire option in either single or double quotes.  Any character  (including  a  back-
           slash)  may  be  included  by  prefixing the character to be included with a backslash.  The file may
           itself contain additional @file options; any such options will be processed recursively.

SEE ALSO
       nm(1), ranlib(1), and the Info entries for binutils.

COPYRIGHT
       Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,  2004,  2005,
       2006, 2007, 2008 Free Software Foundation, Inc.

       Permission  is  granted  to  copy, distribute and/or modify this document under the terms of the GNU Free
       Documentation License, Version 1.2 or any later version published by the Free Software  Foundation;  with
       no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts.  A copy of the license is
       included in the section entitled "GNU Free Documentation License".



binutils-2.18.90                                   2008-09-10                                              AR(1)
 Manual page ar(1) line 159/205 (END)
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from:
如何生成静态连接库？
2004-10-12 10:32:17


静态库及动态库的建立
UNIX系统及各种软件包为开发人员提供了大量的库文件。但一般情况下这些库文件还不能足以满足用户的所有需求。开发人员大多会根据他们自己的开发、研究要求编写出许多函数。对于这些函数，如果都用在命令行中指定源文件的方法同调用它们的程 序链接起来，虽然也是可以的，但也有一些缺点：
.....

下面来看看如何生成静态库。
我们知道静态库也称档案库，在此档案文件中实际上是收集了一系列的目标文件。这 些目标文件就是由cc(gcc)函数的源代码编译生成的。因此，静态库的生成方法实际上 可以分成两步：
1.将各函数代码所在的源文件编译成目录文件。例如，对于myfunc.c，可以用如下命令 将其编译成目标文件：
gcc -c myfunc.c
当然在有多个源文件时，只需在gcc 命令行中将其分别列上就可以了。 经此一步我休养将能够得到各源文件的目标文件。对上例，将得到myfunc.o
2.将各目标文件收集起来放到一个静态库文件中。这主要借助于ar命令完成，如：
ar r ~/lib/libtest.a myfunc.o

建立动态链接库、并不需要用到其他的工具，借助于gcc命令即可完成。此时需在命令 行中加上-K PIC和-G这两个选项，如下我们可以建立libtest的动态版本：
gcc -K PIC -G -o $HOME/lib/libtest.so myfunc.c

--
本来格式很好看的，但因为要贴到这里所以 扭曲了不少，见谅见谅。这里给的是linux下的例子， 但是solaris下的也差不多.

ldd filename就可以看到程序用到哪些库。

ld -o OUTPUT /lib/crt0.o hello.o -lc
ld将输出最终结果文件 OUTPUT ，
用到/lib/crt0.o hello.o以及libc.a
libc.a来自标准库搜索路径，请参看-l选项的讨论

ld的选项顺序任意，可以重复，后面的将覆盖前面的。

gcc -c -fPIC linuxlib.c -O3 -o linuxlib.o
gcc -shared -Wl,-soname,liblinuxlib.so.1 \
-O3 -o liblinuxlib.so.1.0 linuxlib.o
(
ld -m elf_i386 -shared -o liblinuxlib.so.1.0 \
-soname liblinuxlib.so.1 linuxlib.o
这个语句产生的文件更小，不知道二者有何区别
-o liblinuxlib.so.1.0 这个文件名任意，关键是后面
两个符号连接要正确
当然推荐使用有意义的带版本信息的名字，包括
-soname liblinuxlib.so.1
)
ln -sf liblinuxlib.so.1.0 liblinuxlib.so.1
(
运行时，dynamic linker根据 -soname \
liblinuxlib.so.1 去寻找liblinuxlib.so.1
)
ln -sf liblinuxlib.so.1 liblinuxlib.so
(
编译的最后一个步骤，ld命令根据 -llinuxlib
选项去寻找liblinuxlib.so
)
export LD_LIBRARY_PATH=.
(
编译时、运行时都需要这个变量的存在
编译时如果不存在这个变量，编译依旧通过，但
用ldd查看会发现没有动态连接信息
运行时如果不存在这个变量，将报告无法找到动态连接库

这个变量如果不用相对路径"."，换了运行环境就比较麻烦
export LD_LIBRARY_PATH=`pwd`:$LD_LIBRARY_PATH
)
gcc -L. -lbsd -llinuxlib -O3 -o linuxkiller linuxkiller.c
(
-L. 指出除标准库搜索路径之外的库搜索路径，如果不指
定，将找不到liblinuxlib.so
这个选项并不能代替 LD_LIBRARY_PATH 变量，否则虽然编译通过，
但用ldd linuxkiller的时候会发现没有动态连接信息
)

可以把自己的动态连接库放到/usr/lib或者/lib下去，或者
修改/etc/ld.so.conf
然后利用/sbin/ldconfig。具体请man ldconfig

--


发信人: hellguard (小四), 信区: Unix
标 题: Re: help :static library----what's wrong--Thanks.
发信站: BBS 水木清华站 (Thu Aug 16 14:22:39 2001)


【 在 hululu (呼噜噜~回家中) 的大作中提到: 】
: I am building a static library. But I do not know what is
: wrong. Below is a sample:
: tt.c:
: #include
: int func(){
: printf("func test\n");
: return 0;
: }
: ii.c:
: #include
: extern int func();
: ...................
★ 生成静态链接库举例

1. vi demo.h
void demo ( void );

vi demo.c
#include
#include "demo.h"
void demo ( void )
{
printf( "hello world\n" );
return;
}

2. g++ -Wstrict-prototypes -Wall -Wunused -O3 -c demo.c -o demo.o
file demo.o

3. ar -rsv libdemo.a demo.o
a - demo.o
file libdemo.a
nm -s libdemo.a
ar -tv libdemo.a
4. vi scz.c
#include
#include "demo.h"
int main ( int argc, void * argv[] )
{
demo();
return 0;
}

5. g++ scz.c -L. -ldemo -Wstrict-prototypes -Wall -Wunused -O3 -o scz
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