Merge branch 'maint'

* maint:
  Look up IOV_MAX instead of assuming 16

1 files changed, 30 insertions, 3 deletions

diff --git a/erts/emulator/drivers/common/inet_drv.c b/erts/emulator/drivers/common/inet_drv.c
index 00cf260d7b..efb9cbdb77 100644
--- a/erts/emulator/drivers/common/inet_drv.c
+++ b/erts/emulator/drivers/common/inet_drv.c
@@ -1155,9 +1155,24 @@ typedef struct {
 
 #define TCP_MAX_PACKET_SIZE 0x4000000  /* 64 M */
 
-#define MAX_VSIZE 16		/* Max number of entries allowed in an I/O
-				 * vector sock_sendv().
-				 */
+/* Max number of entries allowed in an I/O vector sock_sendv(). */
+#if defined(__WIN32__)
+/* 
+ * Windows 95, 98, and ME is limited to 16, but we do not
+ * support those. Documentation unfortunately does not say
+ * anything about newer windows, so we guess 1024 which
+ * seems to be what most systems use...
+ */
+#define MAX_VSIZE 1024
+#elif !defined(NO_SYSCONF)
+static int iov_max;
+#define MAX_VSIZE iov_max
+#elif defined(IOV_MAX)
+#define MAX_VSIZE IOV_MAX
+#else
+/* POSIX require at least 16 */
+#define MAX_VSIZE 16
+#endif
 
 static int tcp_inet_init(void);
 static void tcp_inet_stop(ErlDrvData);
@@ -4127,6 +4142,18 @@ static int inet_init()
     if (!sock_init())
 	goto error;
 
+#if !defined(__WIN32__) && !defined(NO_SYSCONF)
+    iov_max = (int) sysconf(_SC_IOV_MAX);
+    if (iov_max < 0) {
+#ifdef IOV_MAX
+        iov_max = IOV_MAX;
+#else
+        iov_max = 16; /* min value required by POSIX */
+#endif
+    }
+    ASSERT(iov_max >= 16);
+#endif
+
     if (0 != erl_drv_tsd_key_create("inet_buffer_stack_key", &buffer_stack_key))
 	goto error;