newlib-cygwin/newlib/libc/stdio/tmpfile.c

90 lines
1.8 KiB
C

/*
FUNCTION
<<tmpfile>>---create a temporary file
INDEX
tmpfile
INDEX
_tmpfile_r
SYNOPSIS
#include <stdio.h>
FILE *tmpfile(void);
FILE *_tmpfile_r(struct _reent *<[reent]>);
DESCRIPTION
Create a temporary file (a file which will be deleted automatically),
using a name generated by <<tmpnam>>. The temporary file is opened with
the mode <<"wb+">>, permitting you to read and write anywhere in it
as a binary file (without any data transformations the host system may
perform for text files).
The alternate function <<_tmpfile_r>> is a reentrant version. The
argument <[reent]> is a pointer to a reentrancy structure.
RETURNS
<<tmpfile>> normally returns a pointer to the temporary file. If no
temporary file could be created, the result is NULL, and <<errno>>
records the reason for failure.
PORTABILITY
Both ANSI C and the System V Interface Definition (Issue 2) require
<<tmpfile>>.
Supporting OS subroutines required: <<close>>, <<fstat>>, <<getpid>>,
<<isatty>>, <<lseek>>, <<open>>, <<read>>, <<sbrk>>, <<write>>.
<<tmpfile>> also requires the global pointer <<environ>>.
*/
#include <_ansi.h>
#include <reent.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifndef O_BINARY
# define O_BINARY 0
#endif
FILE *
_DEFUN(_tmpfile_r, (ptr),
struct _reent *ptr)
{
FILE *fp;
int e;
char *f;
char buf[L_tmpnam];
int fd;
do
{
if ((f = _tmpnam_r (ptr, buf)) == NULL)
return NULL;
fd = _open_r (ptr, f, O_RDWR | O_CREAT | O_EXCL | O_BINARY,
S_IRUSR | S_IWUSR);
}
while (fd < 0 && ptr->_errno == EEXIST);
if (fd < 0)
return NULL;
fp = _fdopen_r (ptr, fd, "wb+");
e = ptr->_errno;
if (!fp)
_close_r (ptr, fd);
_CAST_VOID _remove_r (ptr, f);
ptr->_errno = e;
return fp;
}
#ifndef _REENT_ONLY
FILE *
_DEFUN_VOID(tmpfile)
{
return _tmpfile_r (_REENT);
}
#endif