gnome-c-style

gnome-c-style is an Emacs minor mode for editing C source code in GNOME C coding style. In particular, it is useful to properly line-up function arguments and function declarations in header files.

Install

• M-x package-install gnome-c-style
• Add the following line to ~/.emacs.d/init.el:

(add-hook 'c-mode-hook 'gnome-c-style-mode)

Usage

Key	Command
C-c C-g a	Align argument list at the current point
C-c C-g r	Align function declarations in the current region
C-c C-g C-g	Compute optimal alignment columns from the current region
C-c C-g g	Guess alignment columns from the current region
C-c C-g f	Set alignment column to the current point
C-c C-g c	Insert module_object
C-c C-g C	Insert MODULE_OBJECT
C-c C-g C-c	Insert ModuleObject
C-c C-g s	Insert custom snippet

Example

If you have the following code in a header file:

GGpgCtx *g_gpg_ctx_new (GError **error);

typedef void (*GGpgProgressCallback) (gpointer user_data,
                                      const gchar *what,
                                      gint type,
                                      gint current,
                                      gint total);

void g_gpg_ctx_set_progress_callback (GGpgCtx *ctx,
                                      GGpgProgressCallback callback,
                                      gpointer user_data,
                                      GDestroyNotify destroy_data);
void g_gpg_ctx_add_signer (GGpgCtx *ctx, GGpgKey *key);
guint g_gpg_ctx_get_n_signers (GGpgCtx *ctx);
GGpgKey *g_gpg_ctx_get_signer (GGpgCtx *ctx, guint index);
void g_gpg_ctx_clear_signers (GGpgCtx *ctx);

Mark the region, type C-c C-g C-g, and you will see the optimum alignment columns:

identifier-start: 9, arglist-start: 41, arglist-identifier-start: 64

Then, mark the region again, type C-c C-g r, and you will get the code aligned:

GGpgCtx *g_gpg_ctx_new                   (GError              **error);

typedef void (*GGpgProgressCallback) (gpointer user_data,
                                      const gchar *what,
                                      gint type,
                                      gint current,
                                      gint total);

void     g_gpg_ctx_set_progress_callback (GGpgCtx              *ctx,
                                          GGpgProgressCallback  callback,
                                          gpointer              user_data,
                                          GDestroyNotify        destroy_data);
void     g_gpg_ctx_add_signer            (GGpgCtx              *ctx,
                                          GGpgKey              *key);
guint    g_gpg_ctx_get_n_signers         (GGpgCtx              *ctx);
GGpgKey *g_gpg_ctx_get_signer            (GGpgCtx              *ctx,
                                          guint                 index);
void     g_gpg_ctx_clear_signers         (GGpgCtx              *ctx);

Note that the typedef statement is skipped as it is not a function declaration.