Update: Made error IDs an enum.

Thanks to ePirat for the suggestion.

src/client.c

@@ -266,7 +266,7 @@ static inline void _client_send_error(client_t *client, int plain, const icecast
     fserve_add_client (client, NULL);
 }
 
-void client_send_error_by_id(client_t *client, int id)
+void client_send_error_by_id(client_t *client, icecast_error_id_t id)
 {
     const icecast_error_t *error = error_get_by_id(id);
     const char *pref;

src/client.h

@@ -19,6 +19,7 @@
 #ifndef __CLIENT_H__
 #define __CLIENT_H__
 
+#include "errors.h"
 #include "connection.h"
 #include "refbuf.h"
 #include "acl.h"
@@ -109,7 +110,7 @@ typedef struct _client_tag
 
 int client_create (client_t **c_ptr, connection_t *con, http_parser_t *parser);
 void client_destroy(client_t *client);
-void client_send_error_by_id(client_t *client, int id);
+void client_send_error_by_id(client_t *client, icecast_error_id_t id);
 void client_send_101(client_t *client, reuse_t reuse);
 void client_send_426(client_t *client, reuse_t reuse);
 int client_send_bytes (client_t *client, const void *buf, unsigned len);

src/errors.c

@@ -135,7 +135,7 @@ static const icecast_error_t __errors[] = {
      .message = "XSLT problem"}
 };
 
-const icecast_error_t * error_get_by_id(int id) {
+const icecast_error_t * error_get_by_id(icecast_error_id_t id) {
     size_t i;
 
     for (i = 0; i < (sizeof(__errors)/sizeof(*__errors)); i++) {

src/errors.h

@@ -9,48 +9,50 @@
 #ifndef __ERRORS_H__
 #define __ERRORS_H__
 
-#define ICECAST_ERROR_ADMIN_DEST_NOT_RUNNING                   1
-#define ICECAST_ERROR_ADMIN_METADAT_BADCALL                    2
-#define ICECAST_ERROR_ADMIN_METADAT_NO_SUCH_ACTION             3
-#define ICECAST_ERROR_ADMIN_MISSING_PARAMETER                  4
-#define ICECAST_ERROR_ADMIN_missing_parameter                  5 /* what is this? */
-#define ICECAST_ERROR_ADMIN_MOUNT_NOT_ACCEPT_URL_UPDATES       6
-#define ICECAST_ERROR_ADMIN_NO_SUCH_DESTINATION                7
-#define ICECAST_ERROR_ADMIN_ROLEMGN_ADD_NOSYS                  8
-#define ICECAST_ERROR_ADMIN_ROLEMGN_DELETE_NOSYS               9
-#define ICECAST_ERROR_ADMIN_ROLEMGN_ROLE_NOT_FOUND             10
-#define ICECAST_ERROR_ADMIN_SOURCE_DOES_NOT_EXIST              11
-#define ICECAST_ERROR_ADMIN_SOURCE_IS_NOT_AVAILABLE            12
-#define ICECAST_ERROR_ADMIN_SUPPLIED_MOUNTPOINTS_ARE_IDENTICAL 13
-#define ICECAST_ERROR_ADMIN_UNRECOGNISED_COMMAND               14
-#define ICECAST_ERROR_AUTH_BUSY                                15
-#define ICECAST_ERROR_CON_CONTENT_TYPE_NOSYS                   16
-#define ICECAST_ERROR_CON_INTERNAL_FORMAT_ALLOC_ERROR          17
-#define ICECAST_ERROR_CON_MISSING_PASS_PARAMETER               18
-#define ICECAST_ERROR_CON_MOUNT_IN_USE                         19
-#define ICECAST_ERROR_CON_MOUNTPOINT_NOT_STARTING_WITH_SLASH   20
-#define ICECAST_ERROR_CON_NO_CONTENT_TYPE_GIVEN                21
-#define ICECAST_ERROR_CON_PER_CRED_CLIENT_LIMIT                22
-#define ICECAST_ERROR_CON_rejecting_client_for_whatever_reason 23 /* ??? */
-#define ICECAST_ERROR_CON_SOURCE_CLIENT_LIMIT                  24
-#define ICECAST_ERROR_CON_UNIMPLEMENTED                        25
-#define ICECAST_ERROR_CON_UNKNOWN_REQUEST                      26
-#define ICECAST_ERROR_CON_UPGRADE_ERROR                        27
-#define ICECAST_ERROR_FSERV_FILE_NOT_FOUND                     28
-#define ICECAST_ERROR_FSERV_FILE_NOT_READABLE                  29
-#define ICECAST_ERROR_FSERV_REQUEST_RANGE_NOT_SATISFIABLE      30
-#define ICECAST_ERROR_GEN_BUFFER_REALLOC                       31
-#define ICECAST_ERROR_GEN_CLIENT_LIMIT                         32
-#define ICECAST_ERROR_GEN_CLIENT_NEEDS_TO_AUTHENTICATE         33
-#define ICECAST_ERROR_GEN_HEADER_GEN_FAILED                    34
-#define ICECAST_ERROR_GEN_MEMORY_EXHAUSTED                     35
-#define ICECAST_ERROR_SOURCE_MOUNT_UNAVAILABLE                 36
-#define ICECAST_ERROR_SOURCE_STREAM_PREPARATION_ERROR          37
-#define ICECAST_ERROR_XSLT_PARSE                               38
-#define ICECAST_ERROR_XSLT_problem                             39
+typedef enum {
+    ICECAST_ERROR_ADMIN_DEST_NOT_RUNNING,
+    ICECAST_ERROR_ADMIN_METADAT_BADCALL,
+    ICECAST_ERROR_ADMIN_METADAT_NO_SUCH_ACTION,
+    ICECAST_ERROR_ADMIN_MISSING_PARAMETER,
+    ICECAST_ERROR_ADMIN_missing_parameter,                      /* what is this? */
+    ICECAST_ERROR_ADMIN_MOUNT_NOT_ACCEPT_URL_UPDATES,
+    ICECAST_ERROR_ADMIN_NO_SUCH_DESTINATION,
+    ICECAST_ERROR_ADMIN_ROLEMGN_ADD_NOSYS,
+    ICECAST_ERROR_ADMIN_ROLEMGN_DELETE_NOSYS,
+    ICECAST_ERROR_ADMIN_ROLEMGN_ROLE_NOT_FOUND,
+    ICECAST_ERROR_ADMIN_SOURCE_DOES_NOT_EXIST,
+    ICECAST_ERROR_ADMIN_SOURCE_IS_NOT_AVAILABLE,
+    ICECAST_ERROR_ADMIN_SUPPLIED_MOUNTPOINTS_ARE_IDENTICAL,
+    ICECAST_ERROR_ADMIN_UNRECOGNISED_COMMAND,
+    ICECAST_ERROR_AUTH_BUSY,
+    ICECAST_ERROR_CON_CONTENT_TYPE_NOSYS,
+    ICECAST_ERROR_CON_INTERNAL_FORMAT_ALLOC_ERROR,
+    ICECAST_ERROR_CON_MISSING_PASS_PARAMETER,
+    ICECAST_ERROR_CON_MOUNT_IN_USE,
+    ICECAST_ERROR_CON_MOUNTPOINT_NOT_STARTING_WITH_SLASH,
+    ICECAST_ERROR_CON_NO_CONTENT_TYPE_GIVEN,
+    ICECAST_ERROR_CON_PER_CRED_CLIENT_LIMIT,
+    ICECAST_ERROR_CON_rejecting_client_for_whatever_reason,     /* ??? */
+    ICECAST_ERROR_CON_SOURCE_CLIENT_LIMIT,
+    ICECAST_ERROR_CON_UNIMPLEMENTED,
+    ICECAST_ERROR_CON_UNKNOWN_REQUEST,
+    ICECAST_ERROR_CON_UPGRADE_ERROR,
+    ICECAST_ERROR_FSERV_FILE_NOT_FOUND,
+    ICECAST_ERROR_FSERV_FILE_NOT_READABLE,
+    ICECAST_ERROR_FSERV_REQUEST_RANGE_NOT_SATISFIABLE,
+    ICECAST_ERROR_GEN_BUFFER_REALLOC,
+    ICECAST_ERROR_GEN_CLIENT_LIMIT,
+    ICECAST_ERROR_GEN_CLIENT_NEEDS_TO_AUTHENTICATE,
+    ICECAST_ERROR_GEN_HEADER_GEN_FAILED,
+    ICECAST_ERROR_GEN_MEMORY_EXHAUSTED,
+    ICECAST_ERROR_SOURCE_MOUNT_UNAVAILABLE,
+    ICECAST_ERROR_SOURCE_STREAM_PREPARATION_ERROR,
+    ICECAST_ERROR_XSLT_PARSE,
+    ICECAST_ERROR_XSLT_problem
+} icecast_error_id_t;
 
 struct icecast_error_tag {
-    const int id;
+    const icecast_error_id_t id;
     const int http_status;
     const char *uuid;
     const char *message;
@@ -58,6 +60,6 @@ struct icecast_error_tag {
 
 typedef struct icecast_error_tag icecast_error_t;
 
-const icecast_error_t * error_get_by_id(int id);
+const icecast_error_t * error_get_by_id(icecast_error_id_t id);
 
 #endif  /* __ERRORS_H__ */