gdb not launching app - shell

Question

I am trying to run a app using gdb in emulator shell. I use following command
gdb <path of exe>
However, The app does not launch and I get following error
Starting program: <path of exe>
[Thread debugging using libthread_db enabled]
Program exited normally.
However, when I attach a running process to gdb, it works fine.
gdb -pid <process_id>
What could be the reason?
****<Update>****
On Employed Russian's advice, I did these steps
(gdb) b _start
Breakpoint 1 at 0xb40
(gdb) b main
Breakpoint 2 at 0xc43
(gdb) catch syscall exit
Catchpoint 3 (syscall 'exit' [1])
(gdb) catch syscall exit_group
Catchpoint 4 (syscall 'exit_group' [252])
(gdb) r
Starting program: <Exe Path>
[Thread debugging using libthread_db enabled]
Breakpoint 1, 0x80000b40 in _start ()
(gdb) c
Continuing.
Breakpoint 2, 0x80000c43 in main ()
(gdb) c
Continuing.
Catchpoint 4 (call to syscall 'exit_group'), 0xb7fe1424 in __kernel_vsyscall
()
(gdb) c
Continuing.
Program exited normally.
(gdb)
What does Catchpoint 4 (call to syscall 'exit_group'), 0xb7fe1424 in __kernel_vsyscall
this mean?
I probed further and i found this
Single stepping until exit from function main,
which has no line number information.
__libc_start_main (main=0xb6deb030 <main>, argc=1, ubp_av=0xbffffce4,
init=0x80037ab0 <__libc_csu_init>, fini=0x80037b10 <__libc_csu_fini>,
rtld_fini=0xb7ff1000 <_dl_fini>, stack_end=0xbffffcdc) at libc-start.c:258
258 libc-start.c: No such file or directory.
in libc-start.c
However, libc.so is present and i have exported its path also using
export LD_LIBRARY=$LD_LIBRARY:/lib
Why is not loading?

Answer 1

The app does not launch and I get following error
You are mistaken: the app does launch (and the output you get is not an error), and then immediately exits with 0 exit status.
Therefore, you should look at the problem with the app, not a problem with GDB. One way to look at the problem is to set a breakpoint on _start and main, and check whether either of these functions is reached.
If they are, using catch syscall exit or catch syscall exit_group may give you a clue for why the application exits.
Perhaps your application employs anti-reverse-engineering techniques, and detects that it is being debugged?
Update:
you've verified that the application in fact starts, reaches main, and then calls exit. Now all you have to do is figure out why it calls exit. The way to do that is to find out where exit_group system call is coming from.
And to do that, you should get to that system call (Catchpoint 4), issue GDB where command. That will tell you how your application decides to exit.
You also (apparently) built your application without debugging info (usually -g flag). You'll make your debugging easier if you build a debug version of the application.