Linux compiler error that never shown on Visual Studio

let's just admit Visual Studio sux ... ok ?

right now, if you want to host a Private Ragnarok Online server, its just better to choose Debian or CentOS option
the reason is because if you choose Windows Server Edition on VPS,
the cost of running on Windows is often double or triple compare to Linux environment

because of this, programmer like me who write and compile their plugin/source code with Visual Studio,
it will work fine on Windows environment.
But when apply the code on Live server (Linux environment), it will throw non-sensible error

No.1
warning: implicit declaration of function ‘atoi’ [-Wimplicit-function-declaration]

Avoid using atoi like plague !!
in npc scripting its the only script command to convert string into int
yes, this actually working fine with Visual Studio, but on Linux ...

int num = atoi(message); switch(num) { case 0: clif->message(fd, "OFF"); break; default: clif->message(fd, "ON"); break; } <-- change into --> int num = 0; sscanf(message, "%d", &num); switch(num) { case 0: clif->message(fd, "OFF"); break; default: clif->message(fd, "ON"); break; }

No.2
error: a label can only be part of a statement and a declaration is not a statement

Sample
#include "common/hercules.h" #include "map/clif.h" #include "map/atcommand.h" #include "common/strlib.h" #include "plugins/HPMHooking.h" #include "common/HPMDataCheck.h" HPExport struct hplugin_info pinfo = { "test", SERVER_TYPE_MAP, "x.x", HPM_VERSION, }; ACMD(test) { int num; sscanf(message, "%d", &num); switch(num) { case 0: clif->message(fd, "OFF"); return true; default: char msg[CHAT_SIZE_MAX]; safesnprintf(msg, CHAT_SIZE_MAX, "ON %d", num); clif->message(fd, msg); return true; } return true; } HPExport void plugin_init(void) { addAtcommand("test", test); }

default: char msg[CHAT_SIZE_MAX]; safesnprintf(msg, CHAT_SIZE_MAX, "ON %d", num); clif->message(fd, msg); return true; }
this case have to be enclose with curly bracket, like this
ACMD(test) { int num; sscanf(message, "%d", &num); switch(num) { case 0: clif->message(fd, "OFF"); return true; default: { char msg[CHAT_SIZE_MAX]; safesnprintf(msg, CHAT_SIZE_MAX, "ON %d", num); clif->message(fd, msg); return true; } } return true; }

No.3
warning: unused variable ‘len’ [-Wunused-variable]

Sample
#include "common/hercules.h" #include "map/clif.h" #include "common/socket.h" #include "plugins/HPMHooking.h" #include "common/HPMDataCheck.h" HPExport struct hplugin_info pinfo = { "test", SERVER_TYPE_MAP, "x.x", HPM_VERSION, }; static int clif_send_sub_pre(struct block_list **bl, va_list ap) { void *buf = va_arg(ap, void*); int len = va_arg(ap ,int); struct block_list *src_bl = va_arg(ap, struct block_list*); if (src_bl == NULL) return 0; int type = va_arg(ap, int); ShowDebug("%d 0x%x", type, RBUFW(buf, 0)); return 0; } HPExport void plugin_init(void) { addHookPre(clif, send_sub, clif_send_sub_pre); } this is very annoying, because I want to output the value from 4th argument, but the 2nd argument isn't use
on Windows this is fine, but on Linux it throws that error throw off my guard

change
int len = va_arg(ap ,int); <-- change into --> va_arg(ap ,int);

there might be more, will keep this update