1.c

#include <stdio.h>
#include <sys/stat.h> 
#include <fcntl.h>
#include <errno.h>
#include <string.h>

int main (void)
{

  char fn[100];
  int f;

  char basedir[] = "f:\\data\\";
  char current_walfile_name[] = "pg_xlog/fooo";
  snprintf(fn, sizeof(fn), "%s/%s", basedir, current_walfile_name);
  printf("fn: %s\n", fn);
  f = open(fn, O_WRONLY);
  if (f == -1) {
    fprintf(stderr,("could not open transaction log file \"%s\": %s\n"), fn, strerror(errno));
  }

  return 0;
}