gdb trouble

[Neal Becker]

gdb-7.0.1-29.fc12.x86_64

>From time to time, I need to use gdb.  Today it's giving me a real hard 
time.

Breakpoint 3, 0x000000000044f487 in 
ACMTx<boost::random::mersenne_twister<unsigned int, 32, 624, 397, 31, 
2567483615u, 11, 7, 2636928640u, 15, 4022730752u, 18, 3346425566u> 
>::RandomTx() ()
(gdb) s
Single stepping until exit from function 
_ZN5ACMTxIN5boost6random16mersenne_twisterIjLi32ELi624ELi397ELi31ELj2567483615ELi11ELi7ELj2636928640ELi15ELj4022730752ELi18ELj3346425566EEEE8RandomTxEv, 
which has no line number information.

What's going on with the 'single stepping ..."?  Everything was compiled 
with -g (and most or all without optimization).  What could cause the 'no 
line number information'?