Tested on FB 2.5.7 and 3.02 ubuntu_x64 14.04 (two different machines);
On windows fbx64 works ok.

udf return integer by value.

scenario:
more than 2 connections to db
sql : select count(*) from table where validfield(field) = 1 on each connection
table with > 2 milions record

udf written in object pascal ( no memory leaks and other problems)

other implementation this udf in C++ works fine on linux and windows...

stacktrace:
[Thread 0x7fa737789700 (LWP 28692) exited]
[New Thread 0x7fa737789700 (LWP 28693)]
[New Thread 0x7fa736dd7700 (LWP 28694)]
[New Thread 0x7fa73603f700 (LWP 28698)]
An unhandled exception occurred at $00007FA736178E2C:
EStackOverflow: Stack overflow
$00007FA736178E2C
$00007FA7CCFBEC21
$00007FA7CCFBF691
$00007FA7CD0163BA
$00007FA7CCFFD252
$00007FA7CD136DCB
$00007FA7CD13712B
$00007FA7CD131193
$00007FA7CD131D9D
$00007FA7CD13553C
$00007FA7CD041B47
$00007FA7CCEE4C02
$00007FA7CCEE5C35
$00007FA7CCEE807B
$00007FA7CCF0310B
$00007FA7CD087A7E
$00007FA7CD006289



--
Regards,
Michał Kurczabiński