Question

I want to connect to a mysql database with C++ in linux. On my local machine I am running Ubuntu, and installed the mysql server and client packages:

sudo apt-get install mysql-server mysql-client

I came across Mysql++ but have some problems when running ./configure from their binary package. The error says:

checking for MySQL library directory… configure: error: Didn’t find mysqlclient library in ‘/usr/lib64 /usr/lib /usr/lib64/mysql /usr/lib/mysql /usr/local/lib64 /usr/local/lib /usr/local/lib/mysql /usr/local/mysql/lib /usr/local/mysql/lib/mysql /usr/mysql/lib/mysql /opt/mysql/lib /opt/mysql/lib/mysql /sw/lib /sw/lib/mysql’

I see where I can use this command to specify the path:

./configure –with-mysql-lib=/…

but I do not know where to point it to. I used whereis mysql but cannot find any mysql directory that contains a lib subdirectory. Where would the mysqlclient libraries be installed?

---

EDIT:

After doing locate libmysqlclient I got back

/usr/lib/i386-linux-gnu/libmysqlclient.so.18
/usr/lib/i386-linux-gnu/libmysqlclient.so.18.0.0
/usr/lib/i386-linux-gnu/libmysqlclient_r.so.18
/usr/lib/i386-linux-gnu/libmysqlclient_r.so.18.0.0
/usr/share/doc/libmysqlclient18
/usr/share/doc/libmysqlclient18/changelog.Debian.gz
/usr/share/doc/libmysqlclient18/copyright
/var/cache/apt/archives/libmysqlclient18_5.5.22-0ubuntu1_i386.deb
/var/lib/dpkg/info/libmysqlclient18:i386.list
/var/lib/dpkg/info/libmysqlclient18:i386.md5sums
/var/lib/dpkg/info/libmysqlclient18:i386.postinst
/var/lib/dpkg/info/libmysqlclient18:i386.postrm
/var/lib/dpkg/info/libmysqlclient18:i386.shlibs

So, I tried ./configure --with-mysql-lib=/usr/lib/i386-linux-gnu and it seems to complete without any complaining.

Although this solves the problem of getting ./configure to complete, I still have further troubles. When I run make things go fine until this point:

In file included from ./lib/sql_buffer.h:31:0,
from ./lib/sql_buffer.cpp:26: ./lib/refcounted.h:258:2: error: ‘size_t’ does not name a type
./lib/refcounted.h: In constructor ‘mysqlpp::RefCountedPointer::RefCountedPointer()’: ./lib/refcounted.h:89:2: error:
class ‘mysqlpp::RefCountedPointer’ does not have any
field named ‘refs_’ ./lib/refcounted.h: In constructor
‘mysqlpp::RefCountedPointer::RefCountedPointer(T*)’:
./lib/refcounted.h:100:2: error: class ‘mysqlpp::RefCountedPointer’ does not have any field named ‘refs_’
./lib/refcounted.h:104:4: error: ‘refs_’ was not declared in this
scope ./lib/refcounted.h:104:16: error: expected type-specifier before
‘size_t’ ./lib/refcounted.h:104:16: error: expected ‘;’ before
‘size_t’ ./lib/refcounted.h: In constructor
‘mysqlpp::RefCountedPointer::RefCountedPointer(const
ThisType&)’: ./lib/refcounted.h:112:2: error: class
‘mysqlpp::RefCountedPointer’ does not have any field
named ‘refs_’ ./lib/refcounted.h:115:8: error: ‘refs_’ was not
declared in this scope ./lib/refcounted.h: In destructor
‘mysqlpp::RefCountedPointer::~RefCountedPointer()’:
./lib/refcounted.h:125:7: error: ‘refs_’ was not declared in this
scope ./lib/refcounted.h: In member function ‘void
mysqlpp::RefCountedPointer::swap(mysqlpp::RefCountedPointer::ThisType&)’: ./lib/refcounted.h:246:13: error: ‘refs_’ was
not declared in this scope make: *** [mysqlpp_sql_buffer.o] Error 1

I’m not really familiar with C++, so I’m not sure what the error means exactly. Any help or direction on how to get Mysql++ setup from this point would be much appreciated. Although, I admit that I’m also starting to look for alternative libraries to use.

Answer 1

this problem is caused because size_t depends on the inclusion of stddef namespace before it is called in the configuration (make) files.

i had the very same problem (using an amazon EC2 ubuntu 12.04 cloud server) and solved it by editing the offending file (sql_buffer.cpp located, in my case, /home/ubuntu/mysql++-3.1.0/lib) and including stddef (while also moving string namespace up):

#include <stddef.h>
#include <string.h>
#include "sql_buffer.h"

your question is answered with this correction. BUT, you might have additional problems, like i did. so i explain how i solved some subsequent problems, which you might or might not have also.

you might have to use

sudo chown username sql_buffer.cpp

to be able to edit the file, depending on how your install is setup (i am user ubuntu, for example).

i then bumped into another problem:

./ssx/genv2.cpp: In function âbool generate_ssqls2(const char*, const ParseV2*)â:
./ssx/genv2.cpp:70:28: error: âstrcmpâ was not declared in this scope

so i edited the offending file (genv2.cpp) and included string namespace

#include <string.h>

then i had ANOTHER problem with:

./libmysqlpp_ssqls2parse.a(ssqls2parse_parsev2.o): In function `Type':
/home/ubuntu/mysql++-3.1.0/./ssx/parsev2.cpp:256: undefined reference to `mysqlpp::internal::str_to_lwr

i could have edited Makefile.in but chose to simply run in command line:

sudo  g++ -o test_ssqls2 test_ssqls2_ssqls2.o -lmysqlpp_ssqls2parse   -L. -lmysqlclient   -L/usr/lib/x86_64-linux-gnu  -lmysqlpp

i then continued the make process.

that worked for me: mysql++ installed and running.