the length of the placeholder recognized and `strbuf_expand()` skips
over it.
+
+The format `%%` is automatically expanded to a single `%` as a quoting
+mechanism; callers do not need to handle the `%` placeholder themselves,
+and the callback function will not be invoked for this placeholder.
++
All other characters (non-percent and not skipped ones) are copied
verbatim to the strbuf. If the callback returned zero, meaning that the
placeholder is unknown, then the percent sign is copied, too.
placeholder and replacement string. The array needs to be
terminated by an entry with placeholder set to NULL.
+`strbuf_addbuf_percentquote`::
+
+ Append the contents of one strbuf to another, quoting any
+ percent signs ("%") into double-percents ("%%") in the
+ destination. This is useful for literal data to be fed to either
+ strbuf_expand or to the *printf family of functions.
+
`strbuf_addf`::
Add a formatted string to the buffer.