Constify the API and enable -Wwrite-strings

The API is more similar to printf now.

Makefile

@@ -8,7 +8,7 @@ ifeq ($(uname_S),SunOS)
   CFLAGS?= -std=c99 -pedantic $(OPTIMIZATION) -Wall -W -D__EXTENSIONS__ -D_XPG6
   CCLINK?= -ldl -lnsl -lsocket -lm -lpthread
 else
-  CFLAGS?= -std=c99 -pedantic $(OPTIMIZATION) -Wall -W $(ARCH) $(PROF)
+  CFLAGS?= -std=c99 -pedantic $(OPTIMIZATION) -Wall -W -Wwrite-strings $(ARCH) $(PROF)
   CCLINK?= -lm -pthread
 endif
 CCOPT= $(CFLAGS) $(CCLINK) $(ARCH) $(PROF)

anet.c

@@ -125,7 +125,7 @@ int anetResolve(char *err, char *host, char *ipbuf)
 
 #define ANET_CONNECT_NONE 0
 #define ANET_CONNECT_NONBLOCK 1
-static int anetTcpGenericConnect(char *err, char *addr, int port, int flags)
+static int anetTcpGenericConnect(char *err, const char *addr, int port, int flags)
 {
     int s, on = 1;
     struct sockaddr_in sa;
@@ -167,7 +167,7 @@ static int anetTcpGenericConnect(char *err, char *addr, int port, int flags)
     return s;
 }
 
-int anetTcpConnect(char *err, char *addr, int port)
+int anetTcpConnect(char *err, const char *addr, int port)
 {
     return anetTcpGenericConnect(err,addr,port,ANET_CONNECT_NONE);
 }

anet.h

@@ -35,7 +35,7 @@
 #define ANET_ERR -1
 #define ANET_ERR_LEN 256
 
-int anetTcpConnect(char *err, char *addr, int port);
+int anetTcpConnect(char *err, const char *addr, int port);
 int anetTcpNonBlockConnect(char *err, char *addr, int port);
 int anetRead(int fd, char *buf, int count);
 int anetResolve(char *err, char *host, char *ipbuf);

hiredis.c

@@ -50,7 +50,7 @@ static void redisOOM(void) {
  * to the socket file descriptor. On error a redisReply object is returned
  * with reply->type set to REDIS_REPLY_ERROR and reply->string containing
  * the error message. This replyObject must be freed with redisFreeReply(). */
-redisReply *redisConnect(int *fd, char *ip, int port) {
+redisReply *redisConnect(int *fd, const char *ip, int port) {
     char err[ANET_ERR_LEN];
 
     *fd = anetTcpConnect(err,ip,port);
@@ -233,10 +233,10 @@ static void addArgument(sds a, char ***argv, int *argc) {
  * Finally when type is REDIS_REPLY_INTEGER the long long integer is
  * stored at reply->integer.
  */
-redisReply *redisCommand(int fd, char *format, ...) {
+redisReply *redisCommand(int fd, const char *format, ...) {
     va_list ap;
     size_t size;
-    char *arg, *c = format;
+    const char *arg, *c = format;
     sds cmd = sdsempty();     /* whole command buffer */
     sds current = sdsempty(); /* current argument */
     char **argv = NULL;

hiredis.h

@@ -47,8 +47,8 @@ typedef struct redisReply {
     struct redisReply **element; /* elements vector for REDIS_REPLY_ARRAY */
 } redisReply;
 
-redisReply *redisConnect(int *fd, char *ip, int port);
+redisReply *redisConnect(int *fd, const char *ip, int port);
 void freeReplyObject(redisReply *r);
-redisReply *redisCommand(int fd, char *format, ...);
+redisReply *redisCommand(int fd, const char *format, ...);
 
 #endif

sds.c

@@ -116,7 +116,7 @@ static sds sdsMakeRoomFor(sds s, size_t addlen) {
     return newsh->buf;
 }
 
-sds sdscatlen(sds s, void *t, size_t len) {
+sds sdscatlen(sds s, const void *t, size_t len) {
     struct sdshdr *sh;
     size_t curlen = sdslen(s);
 
@@ -130,7 +130,7 @@ sds sdscatlen(sds s, void *t, size_t len) {
     return s;
 }
 
-sds sdscat(sds s, char *t) {
+sds sdscat(sds s, const char *t) {
     return sdscatlen(s, t, strlen(t));
 }
 

sds.h

@@ -48,8 +48,8 @@ size_t sdslen(const sds s);
 sds sdsdup(const sds s);
 void sdsfree(sds s);
 size_t sdsavail(sds s);
-sds sdscatlen(sds s, void *t, size_t len);
-sds sdscat(sds s, char *t);
+sds sdscatlen(sds s, const void *t, size_t len);
+sds sdscat(sds s, const char *t);
 sds sdscpylen(sds s, char *t, size_t len);
 sds sdscpy(sds s, char *t);