【LAMP】Fatal error: Call to undefined function mb_detect_encoding()

我安装LAMP环境，php-xxx-.tar.gz解压缩后的目录 /home/default7/LAMP/php-5.5.13
PHP安装到的目录 /usr/local/php5
然后我安装之后，打开phpmyadmin，报错提示：

Fatal error: Call to undefined function mb_detect_encoding() in /usr/local/apache2/htdocs/phpmyadmin/libraries/php-gettext/gettext.inc on line 177

命令提示行查看php已经安装的模块： mbstring是存在的。

[root@localhost php-5.5.13]# php -m
[PHP Modules]
bz2
calendar
Core
ctype
curl
date
ereg
exif
fileinfo
filter
ftp
gettext
gmp
hash
iconv
json
libxml
mbstring
openssl
pcntl
pcre
Phar
readline
Reflection
session
shmop
SimpleXML
sockets
SPL
standard
tokenizer
xml
zip
zlib

[Zend Modules]

查看phpinfo，相关几个：

PHP Version 5.5.13Configure Command 	'./configure' '--with-apxs2=/usr/local/apache2/bin/apxs' '--with-mysql' '--prefix=/usr/local/php5' Server API 	Apache 2.0 HandlerVirtual Directory Support 	enabledConfiguration File (php.ini) Path 	/usr/local/php5/libLoaded Configuration File 	/usr/local/php5/lib/php.iniScan this dir for additional .ini files 	(none)Additional .ini files parsed 	(none) extension_dir	/usr/local/php5/lib/php/extensions/no-debug-zts-20121212	/usr/local/php5/lib/php/extensions/no-debug-zts-20121212

查看php5安装后的extension目录（是空的）：

[root@localhost ext]# ll /usr/local/php5/lib/php/extensions/no-debug-zts-20121212total 488-rwxr-xr-x. 1 root root 495775 Jun 15 01:01 opcache.so[root@localhost ext]# ll /usr/local/php5/lib/php/extensionstotal 4drwxr-xr-x. 2 root root 4096 Jun 15 01:01 no-debug-zts-20121212

但是在安装后的目录里面另外一个目录却有（目录 /usr/local/php5/include/php/ext）：

[root@localhost ext]# pwd/usr/local/php5/include/php/ext[root@localhost ext]# lltotal 68drwxr-xr-x. 3 root root 4096 Jun 15 01:01 datedrwxr-xr-x. 2 root root 4096 Jun 15 01:01 domdrwxr-xr-x. 3 root root 4096 Jun 15 01:01 eregdrwxr-xr-x. 2 root root 4096 Jun 15 01:01 filterdrwxr-xr-x. 2 root root 4096 Jun 15 01:01 hashdrwxr-xr-x. 2 root root 4096 Jun 15 01:01 iconvdrwxr-xr-x. 2 root root 4096 Jun 15 01:01 jsondrwxr-xr-x. 2 root root 4096 Jun 15 01:01 libxmldrwxr-xr-x. 2 root root 4096 Jun 15 01:02 mysqlnddrwxr-xr-x. 3 root root 4096 Jun 15 01:01 pcredrwxr-xr-x. 2 root root 4096 Jun 15 01:02 pdodrwxr-xr-x. 2 root root 4096 Jun 15 01:01 phardrwxr-xr-x. 2 root root 4096 Jun 15 01:01 sessiondrwxr-xr-x. 2 root root 4096 Jun 15 01:01 spldrwxr-xr-x. 3 root root 4096 Jun 15 01:01 sqlite3drwxr-xr-x. 2 root root 4096 Jun 15 01:02 standarddrwxr-xr-x. 2 root root 4096 Jun 15 01:02 xml[root@localhost ext]# 

在安装文件夹（/home/default7/LAMP/php-5.5.13/ext）中有mbstring：

[root@localhost ext]# lltotal 328drwxr-xr-x.  4 1001 1001  4096 May 28 17:06 bcmathdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 bz2drwxr-xr-x.  3 1001 1001  4096 May 28 17:06 calendardrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 com_dotnetdrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:27 ctypedrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 curldrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:25 datedrwxr-xr-x.  6 1001 1001  4096 May 28 17:06 dbadrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:27 domdrwxr-xr-x.  4 1001 1001  4096 May 28 17:06 enchantdrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:25 eregdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 exif-rwxr-xr-x.  1 1001 1001  8174 May 28 17:06 ext_skel-rw-r--r--.  1 1001 1001  1524 May 28 17:06 ext_skel_win32.phpdrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:27 fileinfodrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:28 filterdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 ftpdrwxr-xr-x.  4 1001 1001  4096 May 28 17:06 gddrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 gettextdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 gmpdrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:43 hashdrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:28 iconvdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 imapdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 interbasedrwxr-xr-x. 20 1001 1001  4096 May 28 17:06 intldrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:28 jsondrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 ldapdrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:26 libxmldrwxr-xr-x.  6 1001 1001  4096 May 28 17:06 mbstringdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 mcryptdrwxr-xr-x.  2 1001 1001  4096 May 28 17:06 mssqldrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:28 mysqldrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 mysqlidrwxr-xr-x.  3 1001 1001  4096 Jun 15 00:32 mysqlnddrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 oci8drwxr-xr-x.  3 1001 1001  4096 May 28 17:06 odbcdrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:35 opcachedrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 openssldrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pcntldrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:26 pcredrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:28 pdodrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_dblibdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_firebirddrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_mysqldrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_ocidrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_odbcdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pdo_pgsqldrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:29 pdo_sqlitedrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pgsqldrwxr-xr-x.  5 1001 1001  4096 Jun 15 01:41 phardrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:29 posixdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 pspelldrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 readlinedrwxr-xr-x.  2 1001 1001  4096 May 28 17:06 recodedrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:29 reflectiondrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:29 sessiondrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 shmopdrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:29 simplexmldrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 skeletondrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 snmpdrwxr-xr-x.  4 1001 1001  4096 May 28 17:06 soapdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 socketsdrwxr-xr-x.  6 1001 1001  4096 Jun 15 00:29 spldrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:26 sqlite3drwxr-xr-x.  5 1001 1001 12288 Jun 15 01:41 standarddrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 sybase_ctdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 sysvmsgdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 sysvsemdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 sysvshmdrwxr-xr-x.  4 1001 1001  4096 May 28 17:06 tidydrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:31 tokenizerdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 wddxdrwxr-xr-x.  4 1001 1001  4096 Jun 15 00:31 xmldrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:31 xmlreaderdrwxr-xr-x.  4 1001 1001  4096 May 28 17:06 xmlrpcdrwxr-xr-x.  5 1001 1001  4096 Jun 15 00:31 xmlwriterdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 xsldrwxr-xr-x.  5 1001 1001  4096 May 28 17:06 zipdrwxr-xr-x.  3 1001 1001  4096 May 28 17:06 zlib

在php.ini中有关extension_dir的都是注释掉了的，但是查看phpinfo却有mysql pdo 这些全都显示。

回复讨论(解决方案)

print_r(get_extension_funcs('mbstring'));
看看都有哪些函数

print_r(get_extension_funcs('mbstring'));
看看都有哪些函数

空的。

那就是没有加载了！
加载了的话应显示

Array(    [0] => mb_convert_case    [1] => mb_strtoupper    [2] => mb_strtolower    [3] => mb_language    [4] => mb_internal_encoding    [5] => mb_http_input    [6] => mb_http_output    [7] => mb_detect_order    [8] => mb_substitute_character    [9] => mb_parse_str    [10] => mb_output_handler    [11] => mb_preferred_mime_name    [12] => mb_strlen    [13] => mb_strpos    [14] => mb_strrpos    [15] => mb_stripos    [16] => mb_strripos    [17] => mb_strstr    [18] => mb_strrchr    [19] => mb_stristr    [20] => mb_strrichr    [21] => mb_substr_count    [22] => mb_substr    [23] => mb_strcut    [24] => mb_strwidth    [25] => mb_strimwidth    [26] => mb_convert_encoding    [27] => mb_detect_encoding    [28] => mb_list_encodings    [29] => mb_encoding_aliases    [30] => mb_convert_kana    [31] => mb_encode_mimeheader    [32] => mb_decode_mimeheader    [33] => mb_convert_variables    [34] => mb_encode_numericentity    [35] => mb_decode_numericentity    [36] => mb_send_mail    [37] => mb_get_info    [38] => mb_check_encoding    [39] => mb_regex_encoding    [40] => mb_regex_set_options    [41] => mb_ereg    [42] => mb_eregi    [43] => mb_ereg_replace    [44] => mb_eregi_replace    [45] => mb_ereg_replace_callback    [46] => mb_split    [47] => mb_ereg_match    [48] => mb_ereg_search    [49] => mb_ereg_search_pos    [50] => mb_ereg_search_regs    [51] => mb_ereg_search_init    [52] => mb_ereg_search_getregs    [53] => mb_ereg_search_getpos    [54] => mb_ereg_search_setpos    [55] => mbregex_encoding    [56] => mbereg    [57] => mberegi    [58] => mbereg_replace    [59] => mberegi_replace    [60] => mbsplit    [61] => mbereg_match    [62] => mbereg_search    [63] => mbereg_search_pos    [64] => mbereg_search_regs    [65] => mbereg_search_init    [66] => mbereg_search_getregs    [67] => mbereg_search_getpos    [68] => mbereg_search_setpos)

那就是没有加载了！
加载了的话应显示

安装解压缩放在 /home/default7/LAMP/php-5.5.13
准备安装在目录 /usr/local/php5

我现在的一个疑问点，对linux ./configure：
如果我第一次在解压缩目录中 ./configure --prefix=... && make && make test && make install …… 安装了。
1）那么我需要新增扩展，是仍旧到这个解压缩目录来./configure --prefix=.. && make && make install 重新编译吗？
2）如果是这样，那么我非首次对这个解压缩文件夹 ./configure ，他参数是否必须全部带齐（是不是这个目录有记忆功能）

我没做过，不好说
网上的教程很多，多看看吧

我没做过，不好说
网上的教程很多，多看看吧

后来安装可以了，重新./configure 安装。
不过要先 make clean，感觉解压缩后./configure了的目录会记忆安装过程。
重新安装带上了 --enable-mbstring之后可以了。之前也重装了几次，但是没有make clean，可能是这个原因。

make clean
./configure --prefix=/usr/local/php5
make
make test
make install

phpinfo();
?>
看看有没有mbstring，如果没有，请检查php.ini