GNU Emacs Manual. Node: Combining in Emerge

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20.14.6: Combining the Two Versions

Sometimes you want to keep both alternatives for a particular difference. To do this, use x c, which edits the merge buffer like this:

#ifdef NEW
version from A buffer
#else /* not NEW */
version from B buffer
#endif /* not NEW */

While this example shows C preprocessor conditionals delimiting the two alternative versions, you can specify the strings to use by setting the variable emerge-combine-versions-template to a string of your choice. In the string, `%a' says where to put version A, and `%b' says where to put version B. The default setting, which produces the results shown above, looks like this:

"#ifdef NEW\n%a#else /* not NEW */\n%b#endif /* not NEW */\n"
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