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| <h3 class="section">10.4 Brief description of <samp><span class="command">gcov</span></samp> data files</h3> |
| |
| <p><samp><span class="command">gcov</span></samp> uses two files for profiling. The names of these files |
| are derived from the original <em>object</em> file by substituting the |
| file suffix with either <samp><span class="file">.gcno</span></samp>, or <samp><span class="file">.gcda</span></samp>. All of these files |
| are placed in the same directory as the object file, and contain data |
| stored in a platform-independent format. |
| |
| <p>The <samp><span class="file">.gcno</span></samp> file is generated when the source file is compiled with |
| the GCC <samp><span class="option">-ftest-coverage</span></samp> option. It contains information to |
| reconstruct the basic block graphs and assign source line numbers to |
| blocks. |
| |
| <p>The <samp><span class="file">.gcda</span></samp> file is generated when a program containing object files |
| built with the GCC <samp><span class="option">-fprofile-arcs</span></samp> option is executed. A |
| separate <samp><span class="file">.gcda</span></samp> file is created for each object file compiled with |
| this option. It contains arc transition counts, and some summary |
| information. |
| |
| <p>The full details of the file format is specified in <samp><span class="file">gcov-io.h</span></samp>, |
| and functions provided in that header file should be used to access the |
| coverage files. |
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