diff --git a/docs/README.md b/docs/README.md
index ef116def..08ddcb2e 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -650,7 +650,7 @@ mg_send(c, "hi", 2);  // Append string "hi" to the output buffer
 
 ```c
 int mg_printf(struct mg_connection *, const char *fmt, ...);
-int mg_vprintf(struct mg_connection *, const char *fmt, va_list ap);
+int mg_vprintf(struct mg_connection *, const char *fmt, va_list *ap);
 ```
 
 Same as `mg_send()`, but formats data using `printf()` semantics. Return
diff --git a/mongoose.c b/mongoose.c
index c90a9827..b72b981a 100644
--- a/mongoose.c
+++ b/mongoose.c
@@ -1607,13 +1607,10 @@ int mg_http_parse(const char *s, size_t len, struct mg_http_message *hm) {
 }
 
 static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
-                                  va_list ap) {
+                                  va_list *ap) {
   size_t len = c->send.len;
-  va_list tmp;
   mg_send(c, "        \r\n", 10);
-  va_copy(tmp, ap);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
-  va_end(tmp);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
   if (c->send.len >= len + 10) {
     mg_snprintf((char *) c->send.buf + len, 9, "%08lx", c->send.len - len - 10);
     c->send.buf[len + 8] = '\r';
@@ -1625,7 +1622,7 @@ static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
 void mg_http_printf_chunk(struct mg_connection *c, const char *fmt, ...) {
   va_list ap;
   va_start(ap, fmt);
-  mg_http_vprintf_chunk(c, fmt, ap);
+  mg_http_vprintf_chunk(c, fmt, &ap);
   va_end(ap);
 }
 
@@ -3277,12 +3274,9 @@ struct mg_connection *mg_mqtt_listen(struct mg_mgr *mgr, const char *url,
 
 
 
-size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list ap) {
+size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
   size_t old = c->send.len;
-  va_list tmp;
-  va_copy(tmp, ap);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
-  va_end(tmp);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
   return c->send.len - old;
 }
 
@@ -3290,7 +3284,7 @@ size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
   size_t len = 0;
   va_list ap;
   va_start(ap, fmt);
-  len = mg_vprintf(c, fmt, ap);
+  len = mg_vprintf(c, fmt, &ap);
   va_end(ap);
   return len;
 }
@@ -6765,7 +6759,6 @@ static void rx_dhcp(struct mip_if *ifp, struct pkt *pkt) {
       uint32_t lease = 0;
       memcpy(&lease, p + 2, sizeof(lease));
       ifp->lease_expire = ifp->now + mg_ntohl(lease) * 1000;
-      // MG_INFO(("LEASEEEEEE %lld", ifp->lease_expire - ifp->now));
     }
     p += p[1] + 2;
   }
diff --git a/mongoose.h b/mongoose.h
index ae74e734..cb4872dd 100644
--- a/mongoose.h
+++ b/mongoose.h
@@ -98,10 +98,6 @@ extern "C" {
 #include <nx_port.h>
 #include <tx_port.h>
 
-#ifdef __REDLIB__
-#define va_copy(d, s) __builtin_va_copy(d, s)
-#endif
-
 #define PATH_MAX FX_MAXIMUM_PATH
 #define MG_DIRSEP '\\'
 
@@ -563,13 +559,6 @@ typedef int socklen_t;
 #define sleep(x) Sleep(x)
 #define mkdir(a, b) _mkdir(a)
 
-#ifndef va_copy
-#ifdef __va_copy
-#define va_copy __va_copy
-#else
-#define va_copy(x, y) (x) = (y)
-#endif
-#endif
 #ifndef S_ISDIR
 #define S_ISDIR(x) (((x) &_S_IFMT) == _S_IFDIR)
 #endif
@@ -1095,7 +1084,7 @@ struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
 void mg_connect_resolved(struct mg_connection *);
 bool mg_send(struct mg_connection *, const void *, size_t);
 size_t mg_printf(struct mg_connection *, const char *fmt, ...);
-size_t mg_vprintf(struct mg_connection *, const char *fmt, va_list ap);
+size_t mg_vprintf(struct mg_connection *, const char *fmt, va_list *ap);
 char *mg_straddr(struct mg_addr *, char *, size_t);
 bool mg_aton(struct mg_str str, struct mg_addr *addr);
 char *mg_ntoa(const struct mg_addr *addr, char *buf, size_t len);
diff --git a/src/arch_azurertos.h b/src/arch_azurertos.h
index aed136fe..6e0e294b 100644
--- a/src/arch_azurertos.h
+++ b/src/arch_azurertos.h
@@ -16,10 +16,6 @@
 #include <nx_port.h>
 #include <tx_port.h>
 
-#ifdef __REDLIB__
-#define va_copy(d, s) __builtin_va_copy(d, s)
-#endif
-
 #define PATH_MAX FX_MAXIMUM_PATH
 #define MG_DIRSEP '\\'
 
diff --git a/src/arch_win32.h b/src/arch_win32.h
index ec3b383b..d8b8e87a 100644
--- a/src/arch_win32.h
+++ b/src/arch_win32.h
@@ -78,13 +78,6 @@ typedef int socklen_t;
 #define sleep(x) Sleep(x)
 #define mkdir(a, b) _mkdir(a)
 
-#ifndef va_copy
-#ifdef __va_copy
-#define va_copy __va_copy
-#else
-#define va_copy(x, y) (x) = (y)
-#endif
-#endif
 #ifndef S_ISDIR
 #define S_ISDIR(x) (((x) &_S_IFMT) == _S_IFDIR)
 #endif
diff --git a/src/http.c b/src/http.c
index 0d37d958..fb046e1f 100644
--- a/src/http.c
+++ b/src/http.c
@@ -267,13 +267,10 @@ int mg_http_parse(const char *s, size_t len, struct mg_http_message *hm) {
 }
 
 static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
-                                  va_list ap) {
+                                  va_list *ap) {
   size_t len = c->send.len;
-  va_list tmp;
   mg_send(c, "        \r\n", 10);
-  va_copy(tmp, ap);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
-  va_end(tmp);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
   if (c->send.len >= len + 10) {
     mg_snprintf((char *) c->send.buf + len, 9, "%08lx", c->send.len - len - 10);
     c->send.buf[len + 8] = '\r';
@@ -285,7 +282,7 @@ static void mg_http_vprintf_chunk(struct mg_connection *c, const char *fmt,
 void mg_http_printf_chunk(struct mg_connection *c, const char *fmt, ...) {
   va_list ap;
   va_start(ap, fmt);
-  mg_http_vprintf_chunk(c, fmt, ap);
+  mg_http_vprintf_chunk(c, fmt, &ap);
   va_end(ap);
 }
 
diff --git a/src/net.c b/src/net.c
index 3d22fea9..c6c500f0 100644
--- a/src/net.c
+++ b/src/net.c
@@ -5,12 +5,9 @@
 #include "timer.h"
 #include "tls.h"
 
-size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list ap) {
+size_t mg_vprintf(struct mg_connection *c, const char *fmt, va_list *ap) {
   size_t old = c->send.len;
-  va_list tmp;
-  va_copy(tmp, ap);
-  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, &tmp);
-  va_end(tmp);
+  mg_vxprintf(mg_pfn_iobuf, &c->send, fmt, ap);
   return c->send.len - old;
 }
 
@@ -18,7 +15,7 @@ size_t mg_printf(struct mg_connection *c, const char *fmt, ...) {
   size_t len = 0;
   va_list ap;
   va_start(ap, fmt);
-  len = mg_vprintf(c, fmt, ap);
+  len = mg_vprintf(c, fmt, &ap);
   va_end(ap);
   return len;
 }
diff --git a/src/net.h b/src/net.h
index 80c8fed7..b01b0fbf 100644
--- a/src/net.h
+++ b/src/net.h
@@ -85,7 +85,7 @@ struct mg_connection *mg_wrapfd(struct mg_mgr *mgr, int fd,
 void mg_connect_resolved(struct mg_connection *);
 bool mg_send(struct mg_connection *, const void *, size_t);
 size_t mg_printf(struct mg_connection *, const char *fmt, ...);
-size_t mg_vprintf(struct mg_connection *, const char *fmt, va_list ap);
+size_t mg_vprintf(struct mg_connection *, const char *fmt, va_list *ap);
 char *mg_straddr(struct mg_addr *, char *, size_t);
 bool mg_aton(struct mg_str str, struct mg_addr *addr);
 char *mg_ntoa(const struct mg_addr *addr, char *buf, size_t len);
diff --git a/test/unit_test.c b/test/unit_test.c
index 125594d5..92662734 100644
--- a/test/unit_test.c
+++ b/test/unit_test.c
@@ -540,7 +540,7 @@ static int fetch(struct mg_mgr *mgr, char *buf, const char *url,
   }
   // c->is_hexdumping = 1;
   va_start(ap, fmt);
-  mg_vprintf(c, fmt, ap);
+  mg_vprintf(c, fmt, &ap);
   va_end(ap);
   buf[0] = '\0';
   for (i = 0; i < 50 && buf[0] == '\0'; i++) mg_mgr_poll(mgr, 1);