/***  REDIRECT.C - Posix-compliant utilities to handle redirection****  written by Benno Sauer, Vienna, 1991**  released into public domain*//***  Modifed 02-Aug-2001by rbs for Win/Solaris**  25-Oct-2001 by RBS - add stderr2stdout()*/#include <stdio.h>#include <fcntl.h>#include <sys/stat.h>#if defined(MSDOS) || defined(__MSDOS__) #include "unistd.h"#else #include <unistd.h>#endif#include "snpdosys.h"/***  Redirect streams to/from files****  Use these predefined structures for the 3 primary streams.**  Define others (e.g. stdprn under DOS) as required.*/REDIR_STRUCT redir_stdin, redir_stdout, redir_stderr;void  start_redirect ( REDIR_STRUCT *s ){      if (s->which == fileno(stdin))            s->where = open ( s->path, O_RDWR, S_IREAD );      else  s->where = open ( s->path, O_CREAT | O_RDWR, S_IREAD | S_IWRITE );      s->oldhandle = dup ( s->which );      dup2  ( s->where, s->which );      close ( s->where );      s->flag = 1;}void  stop_redirect ( REDIR_STRUCT *s ){      if ( s->flag )      {            dup2 ( s->oldhandle, s->which );            close ( s->oldhandle );            s->flag = 0;      }}/***  Special case to redirect stderr to stdout*/void  stderr2stdout ( REDIR_STRUCT *s ){      s->which = fileno(stderr);      s->where = fileno(stdout);      s->oldhandle = dup ( s->which );      dup2  ( s->where, s->which );      s->flag = 1;}#ifdef TEST#include <string.h>main(){      char line[132];      int i;      strcpy(redir_stdin.path, "redirect.c");      redir_stdin.which = fileno(stdin);      strcpy(redir_stdout.path, "x-file");      redir_stdout.which = fileno(stdout);      strcpy(redir_stderr.path, "file.x");      redir_stderr.which = fileno(stderr);      start_redirect(&redir_stdin);      start_redirect(&redir_stdout);      start_redirect(&redir_stderr);      for (i = 1; !feof(stdin); ++i)      {            if (fgets(line, 132, stdin))            {                  fputs(line, stdout);                  fprintf(stderr, "Read line #%d\n", i);            }      }      fflush(stdout);      fflush(stderr);      stop_redirect(&redir_stdin);      stop_redirect(&redir_stdout);      stop_redirect(&redir_stderr);      fputs("All done!\n", stdout);      fflush(stdout);      fputs("Hit Enter to exit\n", stderr);      getchar();      return 0;}#endif /* TEST */