Emacs/docs/latest/emacs/List-Identifiers

28.4.1.4 Identifier Inquiries

C-M-i

M-TAB

Perform completion on the text around point, possibly using the selected tags table if one is loaded (completion-at-point).
M-x xref-find-apropos RET regexp RET: Display a list of all known identifiers matching regexp.
M-x list-tags RET file RET: Display a list of the identifiers defined in the program file file.
M-x tags-next-file: Visit files recorded in the selected tags table.

In most programming language modes, you can type C-M-i or M-TAB (completion-at-point) to complete the symbol at point. Some modes provide specialized completion for this command tailored to the mode; for those that don’t, if there is a tags table loaded, this command can use it to generate completion candidates. See Symbol Completion.

M-x list-tags reads the name of one of the files covered by the selected tags table, and displays a list of tags defined in that file. Do not include a directory as part of the file name unless the file name recorded in the tags table includes a directory. This command works only with the etags backend, and requires a tags table for the project to be available. See Tags Tables. If used interactively, the default tag is file name of the current buffer if used interactively.

M-x tags-next-file visits files covered by the selected tags table. The first time it is called, it visits the first file covered by the table. Each subsequent call visits the next covered file, unless a prefix argument is supplied, in which case it returns to the first file. This command requires a tags table to be selected.