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/* osmsdos/ostext.c */
#include "elvis.h"
#include <sys/types.h>
#include <dos.h>
#include <fcntl.h>
#include <io.h>
#include <errno.h>
/* Microsoft has an annoying habit of adding underscores to the front of
* conventional names.
#ifndef O_WRONLY
# define O_RDWR _O_RDWR
# define O_CREAT _O_CREAT
# define O_EXCL _O_EXCL
# define O_TRUNC _O_TRUNC
# define O_TEXT _O_TEXT
/* This is the fd of the open file */
static int fd;
/* Open a text file for reading (if rwa is 'r') or create/overwrite
* a file for writing (if rwa is 'w') or appending (if rwa is 'a').
* When overwriting an existing file, the file's original permissions
* should be preserved. Returns 0 if successful, -1 if no permission,
* -2 if not a regular file (e.g., a directory), or -3 for other errors.
int txtopen(char *filename, _char_ rwa, ELVBOOL binary)
int flags;
/* try to open the file */
flags = (binary ? O_BINARY : O_TEXT);
switch (rwa)
case 'r': flags |= O_RDONLY; break;
case 'w': flags |= O_WRONLY|O_CREAT|O_TRUNC; break;
case 'a': flags |= O_WRONLY|O_APPEND; break;
fd = open(filename, flags, 0666);
/* return a code indicating the success or reason for failure */
if (fd >= 0)
return 0;
else if (errno == EACCES)
return -1;
else if (errno == EISDIR)
return -2;
return -3;
#if 0
/* if supposed to append, then seek to the end of the file */
if (rwa == 'a')
lseek(fd, 0L, 2);
/* Close the file that was opened by txtopen(). */
void txtclose(void)
/* Append text to a file which has been opened for writing.
* Returns nbytes if successful, or 0 if the disk is full.
* Should perform any necessary translations for converting
* elvis' idea of text into the local OS's idea of text.
int txtwrite(CHAR *buf, int nbytes)
return write(fd, buf, nbytes);
/* Read the next chunk of text from a file. nbytes is the maximum
* number to read. Returns the number of characters actually read
* after any conversions such as CRLF->LF translation.
int txtread(CHAR *buf, int nbytes)
return read(fd, buf, nbytes);