Program received signal SIGTRAP, Trace/breakpoint trap.

[John Smith]

hi,
    when  I  use  'step '  command  to  trace  into  a  function call
, gdb will tell me :

Program received signal SIGTRAP, Trace/breakpoint trap.

The program being debugged was signaled while in a function called from GDB.
GDB has restored the context to what it was before the call.
To change this behavior use "set unwindonsignal off".
Evaluation of the expression containing the function


then I can not  use  'next' to step out  any function call,and
'finish' command  is no usefull .




what is this  problem to be?



thanks in advance!