As described in "Advanced Programming in the UNIX Environment" by Stevens, many
programs use a pattern of mkstemp()/unlink()/write()/close():

 This property of unlink is often used by a program
 to assure that a temporary file it creates won't be
 left around in case the program crashes.  The
 process creates a file using either open or creat
 and then immediately calls unlink.  The file is not
 deleted, however, because it is still open.  Only
 when the process either closes the file or
 terminates (which causes the kernel to close all its
 open files) is the file deleted.

According to the Single Unix Specification, this behavior must be provided by
compliant systems:

 http://www.opengroup.org/onlinepubs/007904975/functions/unlink.html

 When the file's link count becomes 0 and no process
 has the file open, the space occupied by the file
 shall be freed and the file shall no longer be
 accessible. If one or more processes have the file
 open when the last link is removed, the link shall
 be removed before unlink() returns, but the removal
 of the file contents shall be postponed until all
 references to the file are closed.

The below is a testcase.  It will succeed (run forever) on all normal UNIX
filesystems, but fails on every Samba share (including 3.0.1pre1) I have tested
it on.  Compile with:

 gcc -Wall -Werror muw.c -o muw

---- Begin muw.c ----

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define SIZE 1024 * 1024

int
main (int argc, char **argv)
{
  char buff[SIZE];
  int i, fd;

  for (i = 0; i < SIZE; i++)
    buff[i] = 'Z';

  for (;;)
    {
      char name[] = "./muw.XXXXXX";

      if ((fd = mkstemp (name)) == -1)
        {
          fprintf (stderr, "mkstemp failed: %s\n", strerror (errno));
          return 1;
        }

      if (unlink (name))
        {
          fprintf (stderr, "unlink failed: %s\n", strerror (errno));
          return 1;
        }

      fprintf (stdout, "writing %i bytes to %s ...\n", SIZE, name);

      if (write (fd, buff, SIZE) == -1)
        {
          fprintf (stderr, "write failed: %s\n", strerror (errno));
          return 1;
        }
    }

  close (fd);

  return 0;
}

---- End muw.c ----