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| <h2 class="chapter">8 Examining the Stack</h2> |
| |
| <p>When your program has stopped, the first thing you need to know is where it |
| stopped and how it got there. |
| |
| <p><a name="index-call-stack-396"></a>Each time your program performs a function call, information about the call |
| is generated. |
| That information includes the location of the call in your program, |
| the arguments of the call, |
| and the local variables of the function being called. |
| The information is saved in a block of data called a <dfn>stack frame</dfn>. |
| The stack frames are allocated in a region of memory called the <dfn>call |
| stack</dfn>. |
| |
| <p>When your program stops, the <span class="sc">gdb</span> commands for examining the |
| stack allow you to see all of this information. |
| |
| <p><a name="index-selected-frame-397"></a>One of the stack frames is <dfn>selected</dfn> by <span class="sc">gdb</span> and many |
| <span class="sc">gdb</span> commands refer implicitly to the selected frame. In |
| particular, whenever you ask <span class="sc">gdb</span> for the value of a variable in |
| your program, the value is found in the selected frame. There are |
| special <span class="sc">gdb</span> commands to select whichever frame you are |
| interested in. See <a href="Selection.html#Selection">Selecting a Frame</a>. |
| |
| <p>When your program stops, <span class="sc">gdb</span> automatically selects the |
| currently executing frame and describes it briefly, similar to the |
| <code>frame</code> command (see <a href="Frame-Info.html#Frame-Info">Information about a Frame</a>). |
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| <li><a accesskey="1" href="Frames.html#Frames">Frames</a>: Stack frames |
| <li><a accesskey="2" href="Backtrace.html#Backtrace">Backtrace</a>: Backtraces |
| <li><a accesskey="3" href="Selection.html#Selection">Selection</a>: Selecting a frame |
| <li><a accesskey="4" href="Frame-Info.html#Frame-Info">Frame Info</a>: Information on a frame |
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