Dennis Poon wrote / napísal(a):
Jonas Maebe wrote:
On 06 Dec 2013, at 18:45, Dennis Poon wrote:
My server program written in fpc uses sqlite3 and
in ubuntu, I just need to
apt-get install libsqlite3-dev
but in centos, the libsqlite3-dev does not exist and the client lib
after
yum install sqlite
was not enough.
The server program still complained: libsqlite3.so
is missing.
The default behaviour of almost all FPC database units is buggy in
the sense that they look for *.so instead of for *.so.0, *.so.1 or
similar files. The *.so file indeed only exists if you install the
development addendum of a package, and it's just a symlink to the
latest supported version (which is a *.so.0, *.so.1 or similar file).
The only purpose of such a symlink is that in case you link to a
library at compile time, the program will be linked against this
latest installed version (under the assumption that it was also
compiled using the .h files installed on the system, which belong to
this same latest installed version). They should definitely never be
used for dynamic loading, because
a) they generally do not (and should not) exist on user systems
b) they could point to any version, and the unit loading it may not
support that version
In case of FPC, they actually shouldn't be used in case of
compile-time linking either because of point b) above, and we should
again explicitly link to specific versions.
Anyway, you can work around the specific problem you are having by
telling the sqlite unit to use the specifically supported version by
calling InitialiseSQLite('libsqlite.so.0'). It will work on both
Ubuntu and CentOS and any other Linux distribution, and no one will
have to install any -dev packages.
Jonas,
Thanks so much for your help but I tried putting
InitialiseSQLite('libsqlite.so.0')
which did not work.
then I realised, you probably meant
InitialiseSQLite('libsqlite3.so.0');
However, it then complained that "SQLIte interface already initialized
from library libsqlite3.so.0."
I seached files: sqlite3conn.pp, sqlite3dyn.pp, sqlite3.inc,
dynlibs.inc but could not find where InitializeSQLite was called so
could not replace that call from '.so' to '.so.0 '
However, I did find the default library name, used by the function
InitiliseSQLite if no parameter is passed to it, which is composed of
a default file extension defined in file dynlibs.inc
const SharedSuffix = 'so';
Since it is a constant, I dared not change it.
Eventually, I used command
find / -name 'libsqlite3.so*'
and found on this CentOS 64 bit machine:
/usr/lib64/libsqlite3.so.0
/usr/lib64/sw/sqlite37/libsqlite3.so.0
/usr/lib64/sw/sqlite37/libsqlite3.so.0.8.6
/usr/lib64/libsqlite3.so.0.8.6
so, I created a symbolic link in /usr/lib64/
ln -s libsqlite3.so.0 libsqlite3.so
and finally, it worked!
I don't know enough about database in FPC to suggest an improvement
scheme but I do think such one is really in needed for future users.
Did you have tried :
SQLiteLibraryName := 'libsqlite3.so.0'; // SQLiteLibraryName is
defined in sqlite3conn.pp
or
sqlite3dyn.SQLiteDefaultLibrary := 'libsqlite3.so.0';
-Laco.
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