buffer and finds no more error messages to visit, it fails and signals
an Emacs error.
+ You don't have to be in the compilation buffer in order to use
+@code{next-error}. If one window on the selected frame can be the
+target of the @code{next-error} call, it is used. Else, if a buffer
+previously had @code{next-error} called on it, it is used. Else,
+if the current buffer can be the target of @code{next-error}, it is
+used. Else, all the buffers Emacs manages are tried for
+@code{next-error} support.
+
@kbd{C-u C-x `} starts scanning from the beginning of the compilation
buffer. This is one way to process the same set of errors again.