diff --git a/dlls/netapi32/nbcmdqueue.h b/dlls/netapi32/nbcmdqueue.h
index 9eb7075e7f0..57e64118591 100644
--- a/dlls/netapi32/nbcmdqueue.h
+++ b/dlls/netapi32/nbcmdqueue.h
@@ -30,12 +30,12 @@
 struct NBCmdQueue;
 
 /* Allocates a new command queue from heap. */
-struct NBCmdQueue *NBCmdQueueCreate(HANDLE heap);
+struct NBCmdQueue *NBCmdQueueCreate(HANDLE heap) DECLSPEC_HIDDEN;
 
 /* Adds ncb to queue.  Assumes queue is not NULL, and ncb is not already in the
  * queue.  If ncb is already in the queue, returns NRC_TOOMANY.
  */
-UCHAR NBCmdQueueAdd(struct NBCmdQueue *queue, PNCB ncb);
+UCHAR NBCmdQueueAdd(struct NBCmdQueue *queue, PNCB ncb) DECLSPEC_HIDDEN;
 
 /* Cancels the given ncb.  Blocks until the command completes.  Implicitly
  * removes ncb from the queue.  Assumes queue and ncb are not NULL, and that
@@ -44,23 +44,23 @@ UCHAR NBCmdQueueAdd(struct NBCmdQueue *queue, PNCB ncb);
  * completed before it could be cancelled, and various other return values for
  * different failures.
  */
-UCHAR NBCmdQueueCancel(struct NBCmdQueue *queue, PNCB ncb);
+UCHAR NBCmdQueueCancel(struct NBCmdQueue *queue, PNCB ncb) DECLSPEC_HIDDEN;
 
 /* Sets the return code of the given ncb, and implicitly removes the command
  * from the queue.  Assumes queue and ncb are not NULL, and that ncb has been
  * added to queue previously.
  * Returns NRC_GOODRET on success.
  */
-UCHAR NBCmdQueueComplete(struct NBCmdQueue *queue, PNCB ncb, UCHAR retcode);
+UCHAR NBCmdQueueComplete(struct NBCmdQueue *queue, PNCB ncb, UCHAR retcode) DECLSPEC_HIDDEN;
 
 /* Cancels all pending commands in the queue (useful for a RESET or a shutdown).
  * Returns when all commands have been completed.
  */
-UCHAR NBCmdQueueCancelAll(struct NBCmdQueue *queue);
+UCHAR NBCmdQueueCancelAll(struct NBCmdQueue *queue) DECLSPEC_HIDDEN;
 
 /* Frees all memory associated with the queue.  Blocks until all commands
  * pending in the queue have been completed.
  */
-void NBCmdQueueDestroy(struct NBCmdQueue *queue);
+void NBCmdQueueDestroy(struct NBCmdQueue *queue) DECLSPEC_HIDDEN;
 
 #endif /* __NBCMDQUEUE_H__ */
diff --git a/dlls/netapi32/nbnamecache.h b/dlls/netapi32/nbnamecache.h
index ffefbc5b8a1..233f80024e4 100644
--- a/dlls/netapi32/nbnamecache.h
+++ b/dlls/netapi32/nbnamecache.h
@@ -51,7 +51,7 @@ typedef struct _NBNameCacheEntry
 /* Allocates a new name cache from heap, and sets the expire time on new
  * entries to entryExpireTimeMS after a cache entry is added.
  */
-struct NBNameCache *NBNameCacheCreate(HANDLE heap, DWORD entryExpireTimeMS);
+struct NBNameCache *NBNameCacheCreate(HANDLE heap, DWORD entryExpireTimeMS) DECLSPEC_HIDDEN;
 
 /* Adds an entry to the cache.  The entry is assumed to have been allocated
  * from the same heap as the name cache; the name cache will own the entry
@@ -60,14 +60,14 @@ struct NBNameCache *NBNameCacheCreate(HANDLE heap, DWORD entryExpireTimeMS);
  * same name was in the cache, the entry is replaced.  Returns TRUE on success
  * or FALSE on failure.
  */
-BOOL NBNameCacheAddEntry(struct NBNameCache *cache, NBNameCacheEntry *entry);
+BOOL NBNameCacheAddEntry(struct NBNameCache *cache, NBNameCacheEntry *entry) DECLSPEC_HIDDEN;
 
 /* Finds the entry with name name in the cache and returns a pointer to it, or
  * NULL if it isn't found.
  */
 const NBNameCacheEntry *NBNameCacheFindEntry(struct NBNameCache *cache,
- const UCHAR name[NCBNAMSZ]);
+ const UCHAR name[NCBNAMSZ]) DECLSPEC_HIDDEN;
 
-void NBNameCacheDestroy(struct NBNameCache *cache);
+void NBNameCacheDestroy(struct NBNameCache *cache) DECLSPEC_HIDDEN;
 
 #endif /* ndef __WINE_NBNAMECACHE_H */
diff --git a/dlls/netapi32/netbios.h b/dlls/netapi32/netbios.h
index 1279a5ad2fc..4cc9b2edfa7 100644
--- a/dlls/netapi32/netbios.h
+++ b/dlls/netapi32/netbios.h
@@ -32,8 +32,8 @@
  * Public functions
  */
 
-void NetBIOSInit(void);
-void NetBIOSShutdown(void);
+void NetBIOSInit(void) DECLSPEC_HIDDEN;
+void NetBIOSShutdown(void) DECLSPEC_HIDDEN;
 
 struct _NetBIOSTransport;
 
@@ -41,7 +41,7 @@ struct _NetBIOSTransport;
  * a unique id (the transport_id of ACTION_HEADER, for example) and an
  * implementation.  Returns TRUE on success, and FALSE on failure.
  */
-BOOL NetBIOSRegisterTransport(ULONG id, struct _NetBIOSTransport *transport);
+BOOL NetBIOSRegisterTransport(ULONG id, struct _NetBIOSTransport *transport) DECLSPEC_HIDDEN;
 
 /* Registers an adapter with the given transport and ifIndex with NetBIOS.
  * ifIndex is an interface index usable by the IpHlpApi.  ifIndex is not
@@ -51,7 +51,7 @@ BOOL NetBIOSRegisterTransport(ULONG id, struct _NetBIOSTransport *transport);
  * FIXME: need functions for retrieving the name and hardware index, rather
  * than assuming a correlation with IpHlpApi.
  */
-BOOL NetBIOSRegisterAdapter(ULONG transport, DWORD ifIndex, void *adapter);
+BOOL NetBIOSRegisterAdapter(ULONG transport, DWORD ifIndex, void *adapter) DECLSPEC_HIDDEN;
 
 /* During enumeration, all adapters from your transport are disabled
  * internally.  If an adapter is still valid, reenable it with this function.
@@ -59,13 +59,13 @@ BOOL NetBIOSRegisterAdapter(ULONG transport, DWORD ifIndex, void *adapter);
  * function (see below) called on them, and will be removed from the table.
  * (This is to deal with lack of plug-and-play--sorry.)
  */
-void NetBIOSEnableAdapter(UCHAR lana);
+void NetBIOSEnableAdapter(UCHAR lana) DECLSPEC_HIDDEN;
 
 /* Gets a quick count of the number of NetBIOS adapters.  Not guaranteed not
  * to change from one call to the next, depending on what's been enumerated
  * lately.  See also NetBIOSEnumAdapters.
  */
-UCHAR NetBIOSNumAdapters(void);
+UCHAR NetBIOSNumAdapters(void) DECLSPEC_HIDDEN;
 
 typedef struct _NetBIOSAdapterImpl {
     UCHAR lana;
@@ -84,7 +84,7 @@ typedef BOOL (*NetBIOSEnumAdaptersCallback)(UCHAR totalLANAs, UCHAR lanaIndex,
  * Your callback should return FALSE if it no longer wishes to be called.
  */
 void NetBIOSEnumAdapters(ULONG transport, NetBIOSEnumAdaptersCallback cb,
- void *closure);
+ void *closure) DECLSPEC_HIDDEN;
 
 /* Hangs up the session identified in the NCB; the NCB need not be a NCBHANGUP.
  * Will result in the transport's hangup function being called, so release any
@@ -92,7 +92,7 @@ void NetBIOSEnumAdapters(ULONG transport, NetBIOSEnumAdaptersCallback cb,
  * This function is intended for use by a transport, if the session is closed
  * by some error in the transport layer.
  */
-void NetBIOSHangupSession(const NCB *ncb);
+void NetBIOSHangupSession(const NCB *ncb) DECLSPEC_HIDDEN;
 
 /**
  * Functions a transport implementation must implement
@@ -178,6 +178,6 @@ typedef struct _NetBIOSTransport
 /* Not defined by MS, so make my own private define: */
 #define TRANSPORT_NBT "MNBT"
 
-void NetBTInit(void);
+void NetBTInit(void) DECLSPEC_HIDDEN;
 
 #endif /* ndef __WINE_NETBIOS_H__ */
diff --git a/dlls/netapi32/wksta.c b/dlls/netapi32/wksta.c
index 122a6851ce5..ad8d87efb8e 100644
--- a/dlls/netapi32/wksta.c
+++ b/dlls/netapi32/wksta.c
@@ -46,7 +46,7 @@ WINE_DEFAULT_DEBUG_CHANNEL(netapi32);
  *
  * Checks whether the server name indicates local machine.
  */
-BOOL NETAPI_IsLocalComputer(LMCSTR ServerName)
+DECLSPEC_HIDDEN BOOL NETAPI_IsLocalComputer(LMCSTR ServerName)
 {
     if (!ServerName)
     {