title: GDB: how to print function argument values when no name symbols available
body: <p>I'm inspecting a core dump and need to print function arguments values when only their types are known (no argument name symbols):</p>
  
  <pre><code>(gdb) frame 7
  #7  0x00007f201a269e82 in f1(std::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;, unsigned char*, int, std::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;*) () from /usr/lib64/libsome.so
  (gdb) info args
  No symbol table info available.
  (gdb) info f
  Stack level 7, frame at 0x7f200ebf9e50:
   rip = 0x7f201a269e82
      in f1(std::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;, unsigned char*, int, std::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt; &gt;*); saved rip 0x7f201b430905
   called by frame at 0x7f200ebfa1c0, caller of frame at 0x7f200ebf9e00
   Arglist at 0x7f200ebf9df8, args:
   Locals at 0x7f200ebf9df8, Previous frame's sp is 0x7f200ebf9e50
   Saved registers:
    rbx at 0x7f200ebf9e28, rbp at 0x7f200ebf9e30, r12 at 0x7f200ebf9e38, r13 at 0x7f200ebf9e40, rip at 0x7f200ebf9e48
  </code></pre>
  
  <p>Specifically, I need to know what's in the first argument (std::string) and in the last one (std::string*).
  The <em>arglist</em> and the <em>locals</em> in this frame both point to the same address...</p>