Return error messages as 'const char *', not 'char *'.

They're never dynamically allocated, and are almost always string
literals, so const is more appropriate.

1 files changed, 5 insertions, 4 deletions

diff --git a/unruly.c b/unruly.c
index ac5c565..9d2d592 100644
--- a/unruly.c
+++ b/unruly.c
@@ -273,7 +273,7 @@ static game_params *custom_params(const config_item *cfg)
     return ret;
 }
 
-static char *validate_params(const game_params *params, int full)
+static const char *validate_params(const game_params *params, int full)
 {
     if ((params->w2 & 1) || (params->h2 & 1))
         return "Width and height must both be even";
@@ -315,7 +315,7 @@ static char *validate_params(const game_params *params, int full)
     return NULL;
 }
 
-static char *validate_desc(const game_params *params, const char *desc)
+static const char *validate_desc(const game_params *params, const char *desc)
 {
     int w2 = params->w2, h2 = params->h2;
     int s = w2 * h2;
@@ -1174,7 +1174,7 @@ static int unruly_solve_game(game_state *state,
 }
 
 static char *solve_game(const game_state *state, const game_state *currstate,
-                        const char *aux, char **error)
+                        const char *aux, const char **error)
 {
     game_state *solved = dup_game(state);
     struct unruly_scratch *scratch = unruly_new_scratch(solved);
@@ -1972,7 +1972,8 @@ int main(int argc, char *argv[])
 
     game_params *params = NULL;
 
-    char *id = NULL, *desc = NULL, *err;
+    char *id = NULL, *desc = NULL;
+    const char *err;
 
     quis = argv[0];