undefined reference to libiconv_open c++ undefined reference undefined reference to sqrt undefined reference to mai

ext/iconv/.libs/iconv.o: In function `php_iconv_stream_filter_ctor':
/home/king/php-5.2.13/ext/iconv/iconv.c:2491: undefined reference to `libiconv_open'
collect2: ld returned 1 exit status
make: *** [sapi/cli/php] Error 1

Solution:

make ZEND_EXTRA_LIBS='-liconv'

ln -s /usr/local/lib/libiconv.so.2 /usr/lib64/

The above introduces undefined reference to libiconv_open, including the content of reference and undefined. I hope it will be helpful to friends who are interested in PHP tutorials.