[fpc-pascal] how to install sqlite server side library on CentOS

[LacaK]

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.