syscall.Mount returns invalid argument

Question

I have the below simple code, but it fails with invalid argument. I am running this program as root. And the mount point does exist. In ":/vol/share", IP is IP address of NFS server and it is reachable.

package main

import (
    "fmt"
    "syscall"
)   

func nfsMount() {
    // err := syscall.Mount("<IP>:/vol/share", "/mnt/export1", "nfs", 0x0, "")
    err := err := syscall.Mount("IP:/vol/share", "/mnt/export1", "nfs", 0, "")
    if err != nil {
        fmt.Printf("error : %v\n", err.Error())
    }   
}   

func main() {
    nfsMount()
}   

root@~# 
root@~# nfsmount 
error : invalid argument
root@~# 

I have tried the similar program in C.

#include <stdio.h>
#include <sys/mount.h>
#include <errno.h>

void
nfsmount(void)
{
    const char *src = "IP:/vol/share";
    const char *target = "/mnt/export1";
    const char *fsType = "nfs";
    unsigned long mountFlags = 0;
    const void *data = NULL;
    int rc;


    rc = mount(src, target, fsType, mountFlags, "");
    if (rc != 0) {
        printf("mount failed, rc = %d, errno=%d\n", rc, errno);
    }
}

int
main(void)
{
    nfsmount();
}

root@~# cc nfsmount.c -o nfsmountc
root@~#./nfsmountc
mount failed, rc = -1, errno=22
root@~#

It seems to me, this error is some thing to do with data (const void *data)`, the last arg to mount.

When I do the mount through shell, it works.

root@~#  mount -t nfs IP:/vol/share /mnt/export1
root@~# echo $?
0
root@~#  cat /proc/mounts | grep export1
IP:/vol/share /mnt/export1 nfs rw,relatime,vers=3,rsize=65536,wsize=65536,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=IP,mountvers=3,mountport=4046,mountproto=udp,local_lock=none,addr=172.22.14.107 0 0
root@~#  

After some further read, NFS mount System Call in linux helped me. The fix seems: err := syscall.Mount(":/vol/share", "/mnt/export1", "nfs", 0, "nolock,addr=NFSServer>")