Breakpoint not working

[Xavier Brouckaert]

Dear gdb gurus,

I'm trying to debug a vpn client.  Using ltrace -i, I found this :
[0x8052856] vpn_connect(0x8090678, 0x808f408, 0xbfffd7a0, 0xbfffd770,
0 <unfinished ...>
vpn_connect is in a library libvpnapi.so.
When I debug the program using gdb, I set a breakpoint at vpn_connect
with "b vpn_connect" or "b 0x8052856".  Unfortunately, the breakpoint
does not work and execution continues.  Even when I put a "b printf",
the execution continues !

I then wrote a minimal C program with printf and vpn_connect.  When I
debug it, the breakpoints work.

Why is my breakpoint not working with the vpn client ?

Is there a special function in the vpn client which disables breakpoints ?

I would like to have the value of the 4th argument of vpn_client when
the function is called.  I'm sure that this function is called because
I can see it in ltrace every time I launch the program, so the
execution must go through it !

Any idea ?

Thank you !,
Xavier