一開始,調用iconv_open()會返回-1,使用printf("errno=%d\n",errno)查看,返回22,說是invalid argument參數非法。
試了下,確定不是UTF-8或utf-8的大小寫問題。然後按博客http://blog.csdn.net/love_life2011/article/details/7086910#comments所述,更新iconv函數簇爲較新版本後即可。
附http://blog.csdn.net/love_life2011/article/details/7086910#comments內容:
相同的C源程序,在ubuntu11.10上能夠正常執行,而在ARM開發板則不能正常執行,調用
iconv_open("utf-8", "gb2312") 返回失敗,錯誤信息爲“Invalid argument”.
經過查詢資料得知iconv相關函數爲libc中的函數,初步分析得出結論爲有可能是libc版本中
iconv相關函數的版本不同造成的,因此要更新iconv相關函數。
更新iconv相關函數有兩種方法:
第一,更新libc庫;
第二,更新libiconv庫。
第一種方法更新libc庫比較麻煩,因爲我們用的是編譯好的交叉編譯器,這中方法需要重新編譯生成
交叉編譯器,並且也需要使用新編譯生成的交叉編譯工具重新編譯應用程序,因此本方法代價太大,
採用第二種方法。
http://ftp.gnu.org/gnu/libiconv/libiconv-1.14.tar.gz
解壓後得到libiconv目錄,閱讀該目錄下Readme文件得出,編譯安裝libiconv庫也有兩種方式:
This library can be built and installed in two variants:
- The library mode. This works on all systems, and uses a library
`libiconv.so' and a header file `<iconv.h>'. (Both are installed
through "make install".)
To use it, simply #include <iconv.h> and use the functions.
To use it in an autoconfiguring package:
- If you don't use automake, append m4/iconv.m4 to your aclocal.m4
file.
- If you do use automake, add m4/iconv.m4 to your m4 macro repository.
- Add to the link command line of libraries and executables that use
the functions the placeholder @LIBICONV@ (or, if using libtool for
the link, @LTLIBICONV@). If you use automake, the right place for
these additions are the *_LDADD variables.
Note that 'iconv.m4' is also part of the GNU gettext package, which
installs it in /usr/local/share/aclocal/iconv.m4.
- The libc plug/override mode. This works on GNU/Linux, Solaris and OSF/1
systems only. It is a way to get good iconv support without having
glibc-2.1.
It installs a library `preloadable_libiconv.so'. This library can be used
with LD_PRELOAD, to override the iconv* functions present in the C library.
On GNU/Linux and Solaris:
$ export LD_PRELOAD=/usr/local/lib/preloadable_libiconv.so
On OSF/1:
$ export _RLD_LIST=/usr/local/lib/preloadable_libiconv.so:DEFAULT
A program's source need not be modified, the program need not even be
recompiled. Just set the LD_PRELOAD environment variable, that's it!
我在ARM開發板上採用“The libc plug/override mode”實驗成功,下面介紹編譯過程:
在libiconv目錄下:
$./configure --prefix=$PWD/out --host=arm-linux
$make
$make install
上述命令執行完成後會在libiconv目錄下生成新的out目錄,該目錄下存在4個目錄分別是:
bin include lib share
在lib目錄下爲生成的庫文件,其中一個爲preloadable_libiconv.so,把它下載到開發板
的lib目錄下,然後再設置開發板的系統環境變量:
$ export LD_PRELOAD=/lib/preloadable_libiconv.so
然後再執行應用程序即可,正常運行。