ARM开发板上iconv_open("utf-8", "gb2312") 调用失败的解决方法 应用程序代码如下: static int code_convert(char* from_charset, char* to_charset, char* inbuf, size_t inlen, char* outbuf, size_t outlen) { iconv_t cd; char **pin = &inbuf; char **pout = &outbuf; cd = iconv_open(to_charset, from_charset); if (cd == -1) { perror("iconv_open:"); return -1; } memset(outbuf,0,outlen); if (iconv(cd, pin, &inlen, pout, &outlen) == -1) { //printf("%s: call iconv failed!\n", __FUNCTION__); printf("errno=%d\n", errno); perror("iconv failed:\n"); iconv_close(cd); return -1; } iconv_close(cd); return 0; } static int g2u(char* inbuf, size_t inlen, char* outbuf, size_t outlen) { return code_convert("gb2312", "utf-8", inbuf, inlen, outbuf, outlen); } 开发环境为Ubuntu11.10,开发板为ARM开发板,交叉编译器版本为arm-linux-4.4.3. 相同的C源程序,在ubuntu11.10上能够正常执行,而在ARM开发板则不能正常执行,调用 iconv_open("utf-8", "gb2312") 返回失败,错误信息为“Invalid argument”. 经过查询资料得知iconv相关函数为libc中的函数,初步分析得出结论为有可能是libc版本中 iconv相关函数的版本不同造成的,因此要更新iconv相关函数。 更新iconv相关函数有两种方法: 第一,更新libc库; 第二,更新libiconv库。 第一种方法更新libc库比较麻烦,因为我们用的是编译好的交叉编译器,这中方法需要重新编译生成 交叉编译器,并且也需要使用新编译生成的交叉编译工具重新编译应用程序,因此本方法代价太大, 采用第二种方法。 第二种方法为只更新libiconv库,到iconv官网下载最新的库源码包,下载地址为: http://ftp./gnu/libiconv/libiconv-1.14.tar.gz 解压后得到libiconv目录,阅读该目录下Readme文件得出,编译安装libiconv库也有两种方式: 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开发板上采用“The libc plug/override mode”实验成功,下面介绍编译过程: 在libiconv目录下: $./configure --prefix=$PWD/out --host=arm-linux $make $make install 上述命令执行完成后会在libiconv目录下生成新的out目录,该目录下存在4个目录分别是: bin include lib share 在lib目录下为生成的库文件,其中一个为preloadable_libiconv.so,把它下载到开发板 的lib目录下,然后再设置开发板的系统环境变量: $ export LD_PRELOAD=/lib/preloadable_libiconv.so 然后再执行应用程序即可,正常运行。
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