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, 13 insertions, 13 deletions

diff --git a/devel.but b/devel.but
index 98724b3..c7112bb 100644
--- a/devel.but
+++ b/devel.but
@@ -664,7 +664,8 @@ function is never called and need not do anything at all.
 
 \S{backend-validate-params} \cw{validate_params()}
 
-\c char *(*validate_params)(const game_params *params, int full);
+\c const char *(*validate_params)(const game_params *params,
+\c                                int full);
 
 This function takes a \c{game_params} structure as input, and checks
 that the parameters described in it fall within sensible limits. (At
@@ -749,7 +750,8 @@ again in the game description.
 
 \S{backend-validate-desc} \cw{validate_desc()}
 
-\c char *(*validate_desc)(const game_params *params, const char *desc);
+\c const char *(*validate_desc)(const game_params *params,
+\c                              const char *desc);
 
 This function is given a game description, and its job is to
 validate that it describes a puzzle which makes sense.
@@ -1053,7 +1055,7 @@ not even offer the \q{Solve} menu option.
 \S{backend-solve} \cw{solve()}
 
 \c char *(*solve)(const game_state *orig, const game_state *curr,
-\c                const char *aux, char **error);
+\c                const char *aux, const char **error);
 
 This function is called when the user selects the \q{Solve} option
 from the menu.
@@ -3154,8 +3156,8 @@ will probably need to pass it to \cw{midend_set_config}.)
 
 \H{midend-set-config} \cw{midend_set_config()}
 
-\c char *midend_set_config(midend *me, int which,
-\c                         config_item *cfg);
+\c const char *midend_set_config(midend *me, int which,
+\c                               config_item *cfg);
 
 Passes the mid-end the results of a configuration dialog box.
 \c{which} should have the same value which it had when
@@ -3176,7 +3178,7 @@ using \cw{midend_size()} and eventually perform a refresh using
 
 \H{midend-game-id} \cw{midend_game_id()}
 
-\c char *midend_game_id(midend *me, char *id);
+\c const char *midend_game_id(midend *me, char *id);
 
 Passes the mid-end a string game ID (of any of the valid forms
 \cq{params}, \cq{params:description} or \cq{params#seed}) which the
@@ -3244,7 +3246,7 @@ conversion.
 
 \H{midend-solve} \cw{midend_solve()}
 
-\c char *midend_solve(midend *me);
+\c const char *midend_solve(midend *me);
 
 Requests the mid-end to perform a Solve operation.
 
@@ -3316,9 +3318,8 @@ output string.
 
 \H{midend-deserialise} \cw{midend_deserialise()}
 
-\c char *midend_deserialise(midend *me,
-\c                          int (*read)(void *ctx, void *buf, int len),
-\c                          void *rctx);
+\c const char *midend_deserialise(midend *me,
+\c     int (*read)(void *ctx, void *buf, int len), void *rctx);
 
 This function is the counterpart to \cw{midend_serialise()}. It
 calls the supplied \cw{read} function repeatedly to read a quantity
@@ -3355,9 +3356,8 @@ place.
 
 \H{identify-game} \cw{identify_game()}
 
-\c char *identify_game(char **name,
-\c                     int (*read)(void *ctx, void *buf, int len),
-\c                     void *rctx);
+\c const char *identify_game(char **name,
+\c     int (*read)(void *ctx, void *buf, int len), void *rctx);
 
 This function examines a serialised midend stream, of the same kind
 used by \cw{midend_serialise()} and \cw{midend_deserialise()}, and