mingw/info/gdb/Target-Commands.html

   1 <html lang="en">
   2 <head>
   3 <title>Debugging with GDB</title>
   4 <meta http-equiv="Content-Type" content="text/html">
   5 <meta name="description" content="Debugging with GDB">
   6 <meta name="generator" content="makeinfo 4.3">
   7 <link href="http://www.gnu.org/software/texinfo/" rel="generator-home">
   8 </head>
   9 <body>
  10 <div class="node">
  11 <p>
  12 Node:<a name="Target%20Commands">Target Commands</a>,
  13 Next:<a rel="next" accesskey="n" href="Byte-Order.html#Byte%20Order">Byte Order</a>,
  14 Previous:<a rel="previous" accesskey="p" href="Active-Targets.html#Active%20Targets">Active Targets</a>,
  15 Up:<a rel="up" accesskey="u" href="Targets.html#Targets">Targets</a>
  16 <hr><br>
  17 </div>
  18
  19 <h3 class="section">Commands for managing targets</h3>
  20
  21      <dl>
  22 <dt><code>target </code><var>type</var><code> </code><var>parameters</var><code></code>
  23      <dd>Connects the GDB host environment to a target machine or
  24 process.  A target is typically a protocol for talking to debugging
  25 facilities.  You use the argument <var>type</var> to specify the type or
  26 protocol of the target machine.
  27
  28      <p>Further <var>parameters</var> are interpreted by the target protocol, but
  29 typically include things like device names or host names to connect
  30 with, process numbers, and baud rates.
  31
  32      <p>The <code>target</code> command does not repeat if you press &lt;RET&gt; again
  33 after executing the command.
  34
  35      <br><dt><code>help target</code>
  36      <dd>Displays the names of all targets available.  To display targets
  37 currently selected, use either <code>info target</code> or <code>info files</code>
  38 (see <a href="Files.html#Files">Commands to specify files</a>).
  39
  40      <br><dt><code>help target </code><var>name</var><code></code>
  41      <dd>Describe a particular target, including any parameters necessary to
  42 select it.
  43
  44      <br><dt><code>set gnutarget </code><var>args</var><code></code>
  45      <dd>GDB uses its own library BFD to read your files.  GDB
  46 knows whether it is reading an <dfn>executable</dfn>,
  47 a <dfn>core</dfn>, or a <dfn>.o</dfn> file; however, you can specify the file format
  48 with the <code>set gnutarget</code> command.  Unlike most <code>target</code> commands,
  49 with <code>gnutarget</code> the <code>target</code> refers to a program, not a machine.
  50
  51      <blockquote>
  52 <em>Warning:</em> To specify a file format with <code>set gnutarget</code>,
  53 you must know the actual BFD name.
  54 </blockquote>
  55
  56      <p>See <a href="Files.html#Files">Commands to specify files</a>.
  57
  58      <br><dt><code>show gnutarget</code>
  59      <dd>Use the <code>show gnutarget</code> command to display what file format
  60 <code>gnutarget</code> is set to read.  If you have not set <code>gnutarget</code>,
  61 GDB will determine the file format for each file automatically,
  62 and <code>show gnutarget</code> displays <code>The current BDF target is "auto"</code>.
  63 </dl>
  64
  65    <p>Here are some common targets (available, or not, depending on the GDB
  66 configuration):
  67
  68      <dl>
  69 <dt><code>target exec </code><var>program</var><code></code>
  70      <dd>An executable file.  <code>target exec </code><var>program</var><code></code> is the same as
  71 <code>exec-file </code><var>program</var><code></code>.
  72
  73      <br><dt><code>target core </code><var>filename</var><code></code>
  74      <dd>A core dump file.  <code>target core </code><var>filename</var><code></code> is the same as
  75 <code>core-file </code><var>filename</var><code></code>.
  76
  77      <br><dt><code>target remote </code><var>dev</var><code></code>
  78      <dd>Remote serial target in GDB-specific protocol.  The argument <var>dev</var>
  79 specifies what serial device to use for the connection (e.g.
  80 <code>/dev/ttya</code>). See <a href="Remote.html#Remote">Remote debugging</a>.  <code>target remote</code>
  81 supports the <code>load</code> command.  This is only useful if you have
  82 some other way of getting the stub to the target system, and you can put
  83 it somewhere in memory where it won't get clobbered by the download.
  84
  85      <br><dt><code>target sim</code>
  86      <dd>Builtin CPU simulator.  GDB includes simulators for most architectures.
  87 In general,
  88      <pre class="example">                  target sim
  89                   load
  90                   run
  91           </pre>
  92
  93      <p>works; however, you cannot assume that a specific memory map, device
  94 drivers, or even basic I/O is available, although some simulators do
  95 provide these.  For info about any processor-specific simulator details,
  96 see the appropriate section in <a href="Embedded-Processors.html#Embedded%20Processors">Embedded Processors</a>.
  97
  98    </dl>
  99
 100    <p>Some configurations may include these targets as well:
 101
 102      <dl>
 103
 104      <br><dt><code>target nrom </code><var>dev</var><code></code>
 105      <dd>NetROM ROM emulator.  This target only supports downloading.
 106
 107    </dl>
 108
 109    <p>Different targets are available on different configurations of GDB;
 110 your configuration may have more or fewer targets.
 111
 112    <p>Many remote targets require you to download the executable's code
 113 once you've successfully established a connection.
 114
 115      <dl>
 116
 117      <br><dt><code>load </code><var>filename</var><code></code>
 118      <dd>Depending on what remote debugging facilities are configured into
 119 GDB, the <code>load</code> command may be available.  Where it exists, it
 120 is meant to make <var>filename</var> (an executable) available for debugging
 121 on the remote system--by downloading, or dynamic linking, for example.
 122 <code>load</code> also records the <var>filename</var> symbol table in GDB, like
 123 the <code>add-symbol-file</code> command.
 124
 125      <p>If your GDB does not have a <code>load</code> command, attempting to
 126 execute it gets the error message "<code>You can't do that when your
 127 target is ...</code>"
 128
 129      <p>The file is loaded at whatever address is specified in the executable.
 130 For some object file formats, you can specify the load address when you
 131 link the program; for other formats, like a.out, the object file format
 132 specifies a fixed address.
 133
 134      <p><code>load</code> does not repeat if you press &lt;RET&gt; again after using it.
 135 </dl>
 136
 137    </body></html>
 138