Use strict function prototypes #945

`-Wstrict-prototypes` warn if a function is declared or defined without
specifying the argument types.

This warning disallow function prototypes with empty parameter list.
In C, a function declared with an empty parameter list accepts an
arbitrary number of arguments when being called. This is for historic
reasons; originally, C functions didn't have prototypes, as C evolved
from B, a typeless language. When prototypes were added, the original
typeless declarations were left in the language for backwards
compatibility.
Instead we should provide `void` in argument list to state
that function doesn't have arguments.

Also this warning disallow declaring type of the parameters after the
parentheses because Neovim header generator produce no declarations for
old-stlyle prototypes: it expects to find `{` after prototype.

CMakeLists.txt

@@ -29,7 +29,8 @@ if(APPLE)
   endif()
 endif()
 
-add_definitions(-Wall -Wextra -pedantic -Wno-unused-parameter -std=gnu99)
+add_definitions(-Wall -Wextra -pedantic -Wno-unused-parameter
+    -Wstrict-prototypes -std=gnu99)
 
 option(
   TRAVIS_CI_BUILD "Travis CI build.  Extra compilation flags will be set." OFF)

src/nvim/api/private/handle.c

@@ -33,7 +33,7 @@ HANDLE_IMPL(buf_T, buffer)
 HANDLE_IMPL(win_T, window)
 HANDLE_IMPL(tabpage_T, tabpage)
 
-void handle_init()
+void handle_init(void)
 {
   HANDLE_INIT(buffer);
   HANDLE_INIT(window);

src/nvim/api/private/helpers.c

@@ -22,7 +22,7 @@
 #endif
 
 /// Start block that may cause vimscript exceptions
-void try_start()
+void try_start(void)
 {
   ++trylevel;
 }

src/nvim/buffer.c

@@ -4484,7 +4484,7 @@ void buf_delete_signs(buf_T *buf)
 /*
  * Delete all signs in all buffers.
  */
-void buf_delete_all_signs()
+void buf_delete_all_signs(void)
 {
     buf_T *buf;     /* buffer we are checking for signs */
 

src/nvim/eval.c

@@ -11649,9 +11649,7 @@ static void f_readfile(typval_T *argvars, typval_T *rettv)
  * Convert a List to proftime_T.
  * Return FAIL when there is something wrong.
  */
-static int list2proftime(arg, tm)
-typval_T    *arg;
-proftime_T  *tm;
+static int list2proftime(typval_T *arg, proftime_T *tm)
 {
   long n1, n2;
   int error = FALSE;

src/nvim/ex_getln.c

@@ -3932,11 +3932,8 @@ expand_shellcmd (
  * Call "user_expand_func()" to invoke a user defined VimL function and return
  * the result (either a string or a List).
  */
-static void * call_user_expand_func(user_expand_func, xp, num_file, file)
-user_expand_func_T user_expand_func;
-expand_T           *xp;
-int                *num_file;
-char_u             ***file;
+static void * call_user_expand_func(user_expand_func_T user_expand_func,
+                                    expand_T *xp, int *num_file, char_u ***file)
 {
   int keep = 0;
   char_u num[50];

src/nvim/getchar.c

@@ -396,7 +396,7 @@ int stuff_empty(void)
  * Return TRUE if readbuf1 is empty.  There may still be redo characters in
  * redbuf2.
  */
-int readbuf1_empty()
+int readbuf1_empty(void)
 {
   return (readbuf1.bh_first.b_next == NULL);
 }

src/nvim/mbyte.c

@@ -416,7 +416,7 @@ int enc_canon_props(char_u *name)
  * When there is something wrong: Returns an error message and doesn't change
  * anything.
  */
-char_u * mb_init()
+char_u * mb_init(void)
 {
   int i;
   int idx;
@@ -620,7 +620,7 @@ char_u * mb_init()
  * 4 - UCS-4 BOM
  * 3 - UTF-8 BOM
  */
-int bomb_size()
+int bomb_size(void)
 {
   int n = 0;
 
@@ -2850,7 +2850,7 @@ int mb_strnicmp(char_u *s1, char_u *s2, size_t nn)
  * "g8": show bytes of the UTF-8 char under the cursor.  Doesn't matter what
  * 'encoding' has been set to.
  */
-void show_utf8()
+void show_utf8(void)
 {
   int len;
   int rlen = 0;
@@ -3080,7 +3080,7 @@ int mb_tail_off(char_u *base, char_u *p)
 /*
  * Find the next illegal byte sequence.
  */
-void utf_find_illegal()
+void utf_find_illegal(void)
 {
   pos_T pos = curwin->w_cursor;
   char_u      *p;
@@ -3147,7 +3147,7 @@ theend:
  * If the cursor moves on an trail byte, set the cursor on the lead byte.
  * Thus it moves left if necessary.
  */
-void mb_adjust_cursor()
+void mb_adjust_cursor(void)
 {
   mb_adjustpos(curbuf, &curwin->w_cursor);
 }
@@ -3401,7 +3401,7 @@ static int enc_alias_search(char_u *name)
  * Get the canonicalized encoding of the current locale.
  * Returns an allocated string when successful, NULL when not.
  */
-char_u * enc_locale()
+char_u * enc_locale(void)
 {
   char        *s;
   char        *p;
@@ -3696,7 +3696,7 @@ bool iconv_enabled(bool verbose)
   return true;
 }
 
-void iconv_end()
+void iconv_end(void)
 {
   /* Don't use iconv() when inputting or outputting characters. */
   if (input_conv.vc_type == CONV_ICONV)

src/nvim/memory.c

@@ -49,7 +49,7 @@
 
 /// Try to free memory. Used when trying to recover from out of memory errors.
 /// @see {xmalloc}
-static void try_to_free_memory()
+static void try_to_free_memory(void)
 {
   static bool trying_to_free = false;
   // avoid recursive calls

src/nvim/os/channel.c

@@ -56,7 +56,7 @@ static msgpack_sbuffer out_buffer;
 #endif
 
 /// Initializes the module
-void channel_init()
+void channel_init(void)
 {
   channels = pmap_new(uint64_t)();
   event_strings = pmap_new(cstr_t)();
@@ -64,7 +64,7 @@ void channel_init()
 }
 
 /// Teardown the module
-void channel_teardown()
+void channel_teardown(void)
 {
   if (!channels) {
     return;
@@ -470,7 +470,7 @@ static void close_cb(uv_handle_t *handle)
   free(handle);
 }
 
-static Channel *register_channel()
+static Channel *register_channel(void)
 {
   Channel *rv = xmalloc(sizeof(Channel));
   rv->enabled = true;

src/nvim/os/dl.c

@@ -13,7 +13,7 @@
 /// int -> string
 /// string -> string
 /// string -> int
-typedef void (*gen_fn)();
+typedef void (*gen_fn)(void);
 typedef const char *(*str_str_fn)(const char *str);
 typedef int64_t (*str_int_fn)(const char *str);
 typedef const char *(*int_str_fn)(int64_t i);

src/nvim/os/env.c

@@ -55,7 +55,7 @@ char *os_getenvname_at_index(size_t index)
 /// Get the process ID of the Neovim process.
 ///
 /// @return the process ID.
-int64_t os_get_pid()
+int64_t os_get_pid(void)
 {
 #ifdef _WIN32
   return (int64_t)GetCurrentProcessId();

src/nvim/os/event.c

@@ -33,7 +33,7 @@ typedef struct {
 #endif
 static klist_t(Event) *deferred_events, *immediate_events;
 
-void event_init()
+void event_init(void)
 {
   // Initialize the event queues
   deferred_events = kl_init(Event);
@@ -52,7 +52,7 @@ void event_init()
   server_init();
 }
 
-void event_teardown()
+void event_teardown(void)
 {
   channel_teardown();
   job_teardown();
@@ -122,7 +122,7 @@ bool event_poll(int32_t ms)
   return !timer_data.timed_out && (events_processed || event_has_deferred());
 }
 
-bool event_has_deferred()
+bool event_has_deferred(void)
 {
   return !kl_empty(get_queue(true));
 }

src/nvim/os/input.c

@@ -32,20 +32,20 @@ static bool eof = false, started_reading = false;
 // Helper function used to push bytes from the 'event' key sequence partially
 // between calls to os_inchar when maxlen < 3
 
-void input_init()
+void input_init(void)
 {
   read_stream = rstream_new(read_cb, READ_BUFFER_SIZE, NULL, false);
   rstream_set_file(read_stream, read_cmd_fd);
 }
 
 // Listen for input
-void input_start()
+void input_start(void)
 {
   rstream_start(read_stream);
 }
 
 // Stop listening for input
-void input_stop()
+void input_stop(void)
 {
   rstream_stop(read_stream);
 }
@@ -105,14 +105,14 @@ int os_inchar(uint8_t *buf, int maxlen, int32_t ms, int tb_change_cnt)
 }
 
 // Check if a character is available for reading
-bool os_char_avail()
+bool os_char_avail(void)
 {
   return inbuf_poll(0) == kInputAvail;
 }
 
 // Check for CTRL-C typed by reading all available characters.
 // In cooked mode we should get SIGINT, no need to check.
-void os_breakcheck()
+void os_breakcheck(void)
 {
   if (curr_tmode == TMODE_RAW && input_poll(0))
     fill_input_buf(false);
@@ -148,7 +148,7 @@ static InbufPollResult inbuf_poll(int32_t ms)
   return kInputNone;
 }
 
-static void stderr_switch()
+static void stderr_switch(void)
 {
   int mode = cur_tmode;
   // We probably set the wrong file descriptor to raw mode. Switch back to
@@ -198,7 +198,7 @@ static int push_event_key(uint8_t *buf, int maxlen)
 }
 
 // Check if there's pending input
-bool input_ready()
+bool input_ready(void)
 {
   return rstream_available(read_stream) > 0 || eof;
 }

src/nvim/os/job.c

@@ -65,14 +65,14 @@ static uv_prepare_t job_prepare;
 // Callbacks for libuv
 
 /// Initializes job control resources
-void job_init()
+void job_init(void)
 {
   uv_disable_stdio_inheritance();
   uv_prepare_init(uv_default_loop(), &job_prepare);
 }
 
 /// Releases job control resources and terminates running jobs
-void job_teardown()
+void job_teardown(void)
 {
   // 20 tries will give processes about 1 sec to exit cleanly
   uint32_t remaining_tries = 20;

src/nvim/os/server.c

@@ -47,7 +47,7 @@ static PMap(cstr_t) *servers = NULL;
 #endif
 
 /// Initializes the module
-void server_init()
+void server_init(void)
 {
   servers = pmap_new(cstr_t)();
 
@@ -61,7 +61,7 @@ void server_init()
 }
 
 /// Teardown the server module
-void server_teardown()
+void server_teardown(void)
 {
   if (!servers) {
     return;

src/nvim/os/signal.c

@@ -26,7 +26,7 @@ static bool rejecting_deadly;
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "os/signal.c.generated.h"
 #endif
-void signal_init()
+void signal_init(void)
 {
   uv_signal_init(uv_default_loop(), &sint);
   uv_signal_init(uv_default_loop(), &spipe);
@@ -46,7 +46,7 @@ void signal_init()
 #endif
 }
 
-void signal_stop()
+void signal_stop(void)
 {
   uv_signal_stop(&sint);
   uv_signal_stop(&spipe);
@@ -59,12 +59,12 @@ void signal_stop()
 #endif
 }
 
-void signal_reject_deadly()
+void signal_reject_deadly(void)
 {
   rejecting_deadly = true;
 }
 
-void signal_accept_deadly()
+void signal_accept_deadly(void)
 {
   rejecting_deadly = false;
 }

src/nvim/os/time.c

@@ -16,7 +16,7 @@ static uv_cond_t delay_cond;
 # include "os/time.c.generated.h"
 #endif
 /// Initializes the time module
-void time_init()
+void time_init(void)
 {
   uv_mutex_init(&delay_mutex);
   uv_cond_init(&delay_cond);

src/nvim/os_unix.c

@@ -104,7 +104,7 @@ void mch_write(char_u *s, int len)
  * If the machine has job control, use it to suspend the program,
  * otherwise fake it by starting a new shell.
  */
-void mch_suspend()
+void mch_suspend(void)
 {
   /* BeOS does have SIGTSTP, but it doesn't work. */
 #if defined(SIGTSTP) && !defined(__BEOS__)
@@ -148,7 +148,7 @@ void mch_suspend()
 #endif
 }
 
-void mch_init()
+void mch_init(void)
 {
   Columns = 80;
   Rows = 24;
@@ -179,12 +179,12 @@ static int get_x11_icon(int test_only)
 }
 
 
-int mch_can_restore_title()
+int mch_can_restore_title(void)
 {
   return get_x11_title(TRUE);
 }
 
-int mch_can_restore_icon()
+int mch_can_restore_icon(void)
 {
   return get_x11_icon(TRUE);
 }
@@ -292,7 +292,7 @@ int use_xterm_like_mouse(char_u *name)
  * Return 3 for "urxvt".
  * Return 4 for "sgr".
  */
-int use_xterm_mouse()
+int use_xterm_mouse(void)
 {
   if (ttym_flags == TTYM_SGR)
     return 4;
@@ -506,14 +506,15 @@ int mch_nodetype(char_u *name)
   return NODE_WRITABLE;
 }
 
-void mch_early_init()
+void mch_early_init(void)
 {
   handle_init();
   time_init();
 }
 
 #if defined(EXITFREE) || defined(PROTO)
-void mch_free_mem()          {
+void mch_free_mem(void)
+{
   free(oldtitle);
   free(oldicon);
 }
@@ -525,7 +526,7 @@ void mch_free_mem()          {
  * Output a newline when exiting.
  * Make sure the newline goes to the same stream as the text.
  */
-static void exit_scroll()
+static void exit_scroll(void)
 {
   if (silent_mode)
     return;
@@ -691,7 +692,7 @@ void mch_settmode(int tmode)
  * be), they're going to get really annoyed if their erase key starts
  * doing forward deletes for no reason. (Eric Fischer)
  */
-void get_stty()
+void get_stty(void)
 {
   char_u buf[2];
   char_u  *p;
@@ -788,7 +789,7 @@ void mch_setmouse(int on)
 /*
  * Set the mouse termcode, depending on the 'term' and 'ttymouse' options.
  */
-void check_mouse_termcode()
+void check_mouse_termcode(void)
 {
   if (use_xterm_mouse()
       && use_xterm_mouse() != 3
@@ -860,7 +861,7 @@ void check_mouse_termcode()
  * 4. keep using the old values
  * Return OK when size could be determined, FAIL otherwise.
  */
-int mch_get_shellsize()
+int mch_get_shellsize(void)
 {
   long rows = 0;
   long columns = 0;
@@ -937,7 +938,7 @@ int mch_get_shellsize()
 /*
  * Try to set the window size to Rows and Columns.
  */
-void mch_set_shellsize()
+void mch_set_shellsize(void)
 {
   if (*T_CWS) {
     /*

src/nvim/os_unix_defs.h

@@ -41,17 +41,14 @@
 
 #ifdef SIGHASARG
 # ifdef SIGHAS3ARGS
-#  define SIGPROTOARG   (int, int, struct sigcontext *)
-#  define SIGDEFARG(s)  (s, sig2, scont) int s, sig2; struct sigcontext *scont;
+#  define SIGDEFARG(s)  (int s, int sig2, struct sigcontext *scont)
 #  define SIGDUMMYARG   0, 0, (struct sigcontext *)0
 # else
-#  define SIGPROTOARG   (int)
-#  define SIGDEFARG(s)  (s) int s;
+#  define SIGDEFARG(s)  (int s)
 #  define SIGDUMMYARG   0
 # endif
 #else
-# define SIGPROTOARG   (void)
-# define SIGDEFARG(s)  ()
+# define SIGDEFARG(s)  (void)
 # define SIGDUMMYARG
 #endif
 

src/nvim/regexp.c

@@ -274,7 +274,7 @@
  * This is impossible, so we declare a pointer to a function returning a
  * pointer to a function returning void. This should work for all compilers.
  */
-typedef void (*(*fptr_T)(int *, int))();
+typedef void (*(*fptr_T)(int *, int))(void);
 
 typedef struct {
   char_u     *regparse;
@@ -3266,21 +3266,20 @@ bt_regexec_nl (
 }
 
 
-/*
- * Match a regexp against multiple lines.
- * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
- * Uses curbuf for line count and 'iskeyword'.
- *
- * Return zero if there is no match.  Return number of lines contained in the
- * match otherwise.
- */
-static long bt_regexec_multi(rmp, win, buf, lnum, col, tm)
-regmmatch_T *rmp;
-win_T       *win;               /* window in which to search or NULL */
-buf_T       *buf;               /* buffer in which to search */
-linenr_T lnum;                  /* nr of line to start looking for match */
-colnr_T col;                    /* column to start looking for match */
-proftime_T  *tm;                /* timeout limit or NULL */
+/// Matches a regexp against multiple lines.
+/// "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
+/// Uses curbuf for line count and 'iskeyword'.
+/// 
+/// @param win Window in which to search or NULL
+/// @param buf Buffer in which to search
+/// @param lnum Number of line to start looking for match 
+/// @param col Column to start looking for match
+/// @param tm Timeout limit or NULL
+///
+/// @return zero if there is no match and number of lines contained in the match
+///         otherwise.
+static long bt_regexec_multi(regmmatch_T *rmp, win_T *win, buf_T *buf,
+                             linenr_T lnum, colnr_T col, proftime_T *tm)
 {
   long r;
 
@@ -6265,36 +6264,28 @@ static char_u *cstrchr(char_u *s, int c)
 
 
 
-static fptr_T do_upper(d, c)
-int         *d;
-int c;
+static fptr_T do_upper(int *d, int c)
 {
   *d = vim_toupper(c);
 
   return (fptr_T)NULL;
 }
 
-static fptr_T do_Upper(d, c)
-int         *d;
-int c;
+static fptr_T do_Upper(int *d, int c)
 {
   *d = vim_toupper(c);
 
   return (fptr_T)do_Upper;
 }
 
-static fptr_T do_lower(d, c)
-int         *d;
-int c;
+static fptr_T do_lower(int *d, int c)
 {
   *d = vim_tolower(c);
 
   return (fptr_T)NULL;
 }
 
-static fptr_T do_Lower(d, c)
-int         *d;
-int c;
+static fptr_T do_Lower(int *d, int c)
 {
   *d = vim_tolower(c);
 

src/nvim/regexp_nfa.c

@@ -6338,38 +6338,42 @@ nfa_regexec_nl (
   return nfa_regexec_both(line, col) != 0;
 }
 
-/*
- * Match a regexp against multiple lines.
- * "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
- * Uses curbuf for line count and 'iskeyword'.
- *
- * Return zero if there is no match.  Return number of lines contained in the
- * match otherwise.
- *
- * Note: the body is the same as bt_regexec() except for nfa_regexec_both()
- *
- * ! Also NOTE : match may actually be in another line. e.g.:
- * when r.e. is \nc, cursor is at 'a' and the text buffer looks like
- *
- * +-------------------------+
- * |a                        |
- * |b                        |
- * |c                        |
- * |                         |
- * +-------------------------+
- *
- * then nfa_regexec_multi() returns 3. while the original
- * vim_regexec_multi() returns 0 and a second call at line 2 will return 2.
- *
- * FIXME if this behavior is not compatible.
- */
-static long nfa_regexec_multi(rmp, win, buf, lnum, col, tm)
-regmmatch_T *rmp;
-win_T       *win;               /* window in which to search or NULL */
-buf_T       *buf;               /* buffer in which to search */
-linenr_T lnum;                  /* nr of line to start looking for match */
-colnr_T col;                    /* column to start looking for match */
-proftime_T  *tm;         /* timeout limit or NULL */
+/// Matches a regexp against multiple lines.
+/// "rmp->regprog" is a compiled regexp as returned by vim_regcomp().
+/// Uses curbuf for line count and 'iskeyword'.
+///
+/// @param win Window in which to search or NULL
+/// @param buf Buffer in which to search
+/// @param lnum Number of line to start looking for match
+/// @param col Column to start looking for match
+/// @param tm Timeout limit or NULL
+///
+/// @return Zero if there is no match and number of lines contained in the match
+/// otherwise.
+///
+/// @note The body is the same as bt_regexec() except for nfa_regexec_both()
+///
+/// @warning
+/// Match may actually be in another line. e.g.:
+/// when r.e. is \nc, cursor is at 'a' and the text buffer looks like
+///
+/// @par
+///
+///     +-------------------------+
+///     |a                        |
+///     |b                        |
+///     |c                        |
+///     |                         |
+///     +-------------------------+
+///
+/// @par
+/// then nfa_regexec_multi() returns 3. while the original vim_regexec_multi()
+/// returns 0 and a second call at line 2 will return 2.
+///
+/// @par
+/// FIXME if this behavior is not compatible.
+static long nfa_regexec_multi(regmmatch_T *rmp, win_T *win, buf_T *buf,
+                              linenr_T lnum, colnr_T col, proftime_T *tm)
 {
   reg_match = NULL;
   reg_mmatch = rmp;

src/nvim/screen.c

@@ -639,7 +639,7 @@ void update_single_line(win_T *wp, linenr_T lnum)
  * Prepare for updating one or more windows.
  * Caller must check for "updating_screen" already set to avoid recursiveness.
  */
-static void update_prepare()
+static void update_prepare(void)
 {
     cursor_off();
     updating_screen = TRUE;
@@ -649,7 +649,7 @@ static void update_prepare()
 /*
  * Finish updating one or more windows.
  */
-static void update_finish()
+static void update_finish(void)
 {
     if (redraw_cmdline) {
         showmode();

src/nvim/term.c

@@ -67,7 +67,7 @@
  * A few linux systems define outfuntype in termcap.h to be used as the third
  * argument for tputs().
  */
-#   define TPUTSFUNCAST (int (*)())
+#   define TPUTSFUNCAST (int (*)(int))
 #endif
 
 #undef tgetstr