How does FPC determine which SQLite shared library to link to on
Linux?
lazarus / 63-Database

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PierceNg · 2020-08-23 12:29

I'm on Ubuntu and Alpine Linux. I'm using this SQLite binding:

  https://github.com/plashenkov/SQLite3-Delphi-FPC

Example program:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i program
dbtest; {$mode objfpc}{$H+} uses  SQLite3Wrap; const  DatabaseFileName
= 'x.db';  Schema = 'create table if not exists x (' +    'id integer
primary key, ' +    'x varchar' +    ')';  InsertSQL = 'insert into x
values (NULL, ?)'; var  db: TSQLite3Database;  stmt:
TSQLite3Statement; begin  try    db := TSQLite3Database.create;   
db.open(DatabaseFileName);     db.beginTransaction;   
db.execute(Schema);    db.commit;     stmt := db.prepare(InsertSQL); 
 stmt.bindText(1, '42');    db.beginTransaction;   
stmt.stepAndReset;    db.commit;  finally    stmt.free;    db.free; 
end;end. 
The SQLite binding defines the following:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
const{$IFDEF MSWINDOWS}  sqlite3_lib = 'sqlite3.dll';{$ENDIF}{$IFDEF
UNIX}  sqlite3_lib = 'sqlite3.so';{$ENDIF}{$IFDEF DARWIN}  sqlite3_lib
= 'libsqlite3.dylib';{$ENDIF}
All SQLite functions are declared in similar style:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
sqlite3_libversion: PAnsiChar; cdecl; external sqlite3_lib;
Compile my example program:

Code: Bash  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i % fpc
dbtest.pasfpc dbtest.pasFree Pascal Compiler version 3.2.0
[2020/07/07] for x86_64Copyright (c) 1993-2020 by Florian Klaempfl and
othersTarget OS: Linux for x86-64Compiling dbtest.pasLinking dbtest42
lines compiled, 0.2 sec
By default the executable links to the system-provided SQLite shared
library:

Code: Bash  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i % ldd
dbtest        linux-vdso.so.1 (0x00007ffdad689000)       
libsqlite3.so.0 => /lib/x86_64-linux-gnu/libsqlite3.so.0
(0x00007ff044862000)        libm.so.6 => /lib/x86_64-linux-
gnu/libm.so.6 (0x00007ff044713000)        libpthread.so.0 =>
/lib/x86_64-linux-gnu/libpthread.so.0 (0x00007ff0446f0000)       
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007ff0446ea000)  
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007ff0444f8000) 
      /lib64/ld-linux-x86-64.so.2 (0x00007ff0449a4000)
How to tell FPC to link to my self-compiled libsqlite3.so? I want to
use my own libsqlite3.so to make sure that the SQLite functionality my
program uses is indeed in the shared library the program links to.

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julkas · 2020-08-23 12:50

See option -Fl - https://www.freepascal.org/docs-
html/current/user/userap1.html

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PierceNg · 2020-08-23 15:24

Quote from: julkas on August 23, 2020, 02:50:04 pmSee option -Fl -
https://www.freepascal.org/docs-html/current/user/userap1.html

Thank you.