title: gdb | view the variable argument list
body: <p>I as using the <code>bt</code> command to view the stacktrace. The output is</p>
  
  <pre><code>(gdb) bt
  #0  0x001ae4cd in Debugger (message=0x1 "???\a") at /SourceCache/xnu/xnu-1228.7.58/osfmk/i386/AT386/model_dep.c:705
  #1  0x3bf97000 in ?? ()
  #2  0x0012b0fa in panic (str=0x5ef "") at /SourceCache/xnu/xnu-1228.7.58/osfmk/kern/debug.c:274
  #3  0x001a8cd4 in kernel_trap (state=0x51a67c80) at /SourceCache/xnu/xnu-1228.7.58/osfmk/i386/trap.c:680
  #4  0x0019ede5 in return_from_trap () at pmap.h:176
  #5  0x00132bea in __doprnt (fmt=&lt;value temporarily unavailable, due to optimizations&gt;, argp=0x51a67e6c, putc=0x38ad24 &lt;kvprintf+33&gt;, arg=0x51a67e48, radix=10) at /SourceCache/xnu/xnu-1228.7.58/osfmk/kern/printf.c:439
  #6  0x0038ad11 in kvprintf (fmt=0x1 "???\a", func=0x1, arg=0x1, radix=1, ap=0x51a67e84 "\\?\034I\"") at /SourceCache/xnu/xnu-1228.7.58/bsd/kern/subr_prf.c:525
  #7  0x491b5dac in com_my_drv_Log (format=0x491cbff8 "%s::%s:%n\n") at Logger.cpp:37
  #8  0x491b3d36 in MyDrv::init (this=0x5c1f200, properties=0x58a8040) at MyDrv.cpp:34
  #9  0x00412887 in IOService::probeCandidates (this=0x599a980, matches=0x58ade80) at /SourceCache/xnu/xnu-1228.7.58/iokit/Kernel/IOService.cpp:2512
  #10 0x004124ab in IOService::doServiceMatch (this=0x534180, options=8) at /SourceCache/xnu/xnu-1228.7.58/iokit/Kernel/IOService.cpp:2921
  #11 0x00411127 in _IOConfigThread::main (self=0x58c6790) at /SourceCache/xnu/xnu-1228.7.58/iokit/Kernel/IOService.cpp:3125
  (gdb) 
  </code></pre>
  
  <p>In frame</p>
  
  <pre><code>#7  0x491b5dac in com_my_drv_Log
  </code></pre>
  
  <p>how could I view the parameters passed to my <code>com_my_drv_Log</code> with signature</p>
  
  <pre><code>void com_my_drv_Log (const char* format, ...);
  /* with the variable argument list */
  </code></pre>
  
  <p>?</p>