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, 3 insertions, 3 deletions

diff --git a/filling.c b/filling.c
index 585b4bd..6f775f4 100644
--- a/filling.c
+++ b/filling.c
@@ -184,7 +184,7 @@ 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->w < 1) return "Width must be at least one";
     if (params->h < 1) return "Height must be at least one";
@@ -1266,7 +1266,7 @@ static char *new_game_desc(const game_params *params, random_state *rs,
     return sresize(description, j, char);
 }
 
-static char *validate_desc(const game_params *params, const char *desc)
+static const char *validate_desc(const game_params *params, const char *desc)
 {
     const int sz = params->w * params->h;
     const char m = '0' + max(max(params->w, params->h), 3);
@@ -1338,7 +1338,7 @@ static void free_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)
 {
     if (aux == NULL) {
         const int w = state->shared->params.w;