如何链接glibc的iconv实现？

Question

GNU C库提供了iconv的实现--我该如何使用它？

简单的程序：

#include <iconv.h>

int main( int argc, char **argv ) {
        iconv_t cd = iconv_open( "UTF-8", "ISO-8859-1" );
        iconv_close( cd );
        return 0;
}

编译和链接：

$ gcc -Wall iconv.c -o iconv
/tmp/ccKAfXNg.o: In function `main':
iconv.c:(.text+0x19): undefined reference to `libiconv_open'
iconv.c:(.text+0x29): undefined reference to `libiconv_close'
collect2: ld returned 1 exit status

列出符号以显示它们的存在！

$ nm -D /lib/libc-2.12.1.so | grep iconv
00017920 T iconv
00017ae0 T iconv_close
00017720 T iconv_open

如果我将GNU libiconv库安装到/usr/local并链接到-liconv，它就可以工作。如何链接到iconv的glibc实现？

编辑:根据评论的要求提供更多信息：

列出/usr中的所有iconv.h文件(1个匹配项)

$ find /usr/ | grep "iconv\.h"
/usr/include/iconv.h

重新安装libc6-dev以确保安装了正确的头文件。

$ dpkg -S /usr/include/iconv.h 
libc6-dev: /usr/include/iconv.h
$ apt-get install --reinstall libc6-dev
Reading package lists... Done                                                                                                                                                                                                                  
Building dependency tree                                                                                                                                                                                                                       
Reading state information... Done                                                                                                                                                                                                              
0 upgraded, 0 newly installed, 1 reinstalled, 0 to remove and 0 not upgraded.                                                                                                                                                                  
Need to get 0B/4,910kB of archives.                                                                                                                                                                                                            
After this operation, 0B of additional disk space will be used.                                                                                                                                                                                
(Reading database ... 143458 files and directories currently installed.)                                                                                                                                                                       
Preparing to replace libc6-dev 2.12.1-0ubuntu10.1 (using .../libc6-dev_2.12.1-0ubuntu10.1_i386.deb) ...                                                                                                                                        
Unpacking replacement libc6-dev ...                                                                                                                                                                                                            
Setting up libc6-dev (2.12.1-0ubuntu10.1) ...

使用建议的预处理器选项重新编译和链接：

$ gcc -Wall -DLIBICONV_PLUG iconv.c -o iconv
/tmp/ccKAfXNg.o: In function `main':
iconv.c:(.text+0x19): undefined reference to `libiconv_open'
iconv.c:(.text+0x29): undefined reference to `libiconv_close'
collect2: ld returned 1 exit status

来自gcc -H的输出：

$ gcc -H iconv.c 
. /usr/include/iconv.h
.. /usr/include/features.h
... /usr/include/bits/predefs.h
... /usr/include/sys/cdefs.h
.... /usr/include/bits/wordsize.h
... /usr/include/gnu/stubs.h
.... /usr/include/bits/wordsize.h
.... /usr/include/gnu/stubs-32.h
.. /usr/lib/gcc/i686-linux-gnu/4.4.5/include/stddef.h
Multiple include guards may be useful for:
/usr/include/bits/predefs.h
/usr/include/gnu/stubs-32.h
/usr/include/gnu/stubs.h
/usr/lib/gcc/i686-linux-gnu/4.4.5/include/stddef.h

pastbin copy of /usr/include/iconv.h

已修复:重新启动已修复此问题。我怀疑libiconv的缓存副本导致了冲突，尽管它已从磁盘中删除。

Answer 1

您的程序看起来很好，并且在我的系统(Mandriva Linux 2010.1)上编译得很好。

不过，我发现编译日志中的libiconv_*引用令人担忧。您确定包含的iconv.h版本来自glibc，而不是来自单独的libiconv实现，例如GNU libiconv？听起来好像它为所有的iconv函数添加了一个lib前缀，以避免与系统附带的C库的iconv实现发生符号冲突。

必须显式链接到libiconv也指向单独的iconv实现- glibc不需要它。

编辑：

根据记录，我刚刚验证了使用libiconv中的iconv.h头文件而不显式链接它是否会产生您所看到的结果-它通过为所有iconv函数的名称添加一个lib前缀来重命名它们。