martin@humu.UUCP (Douglas W. Martin) (12/18/86)
Can soneone help me figure out how to write unformatted,
sequential files in F77, such that they do not contain header info?
In PDP-11 Fortran, there existed functions iread and iwrite, with matching
read and write functions in assembly language. It was thus quite easy to
write a file as output from an assembly language program, and later
read that file as input to a Fortran program. How can this be done in F77?
Thanks in advance,
Doug Martin
NOSC-Hawaii Laboratories
UUCPmail: {akgua,allegra,decvax,ihnp4,ucbvax}!sdcsvax!noscvax!martin
MILNET: martin@NOSCpjw@alice.UUCP (12/22/86)
fortran unformatted output has to contain some kind of record boundaries so BACKSPACE works. The most likely way to write a binary file from some other language and read it using fortran is to write fixed length records and use f77 direct i/o. (fortran's not a language that cooperates well with anything else)
jerry@opal.berkeley.edu (Jerry Berkman) (12/23/86)
In article <407@humu.UUCP> martin@humu.UUCP (Douglas W. Martin) writes: > > > Can soneone help me figure out how to write unformatted, >sequential files in F77, such that they do not contain header info? >How can this be done in F77? >Thanks in advance, >Doug Martin >NOSC-Hawaii Laboratories 4.x BSD VAX UNIX includes putc(ch) and fputc(lunit,ch) functions which write a character to a logical unit with no headers, or new lines. There are corresponding getc() and fgetc() function. See "man 3f putc" and "man 3f getc" for details. - Jerry Berkman Academic Computing Services, U. C. Berkeley (415) 642-4804 jerry@ucbopal.Berkeley.EDU
rchrd@well.UUCP (Richard Friedman) (12/30/86)
Yuk! I wouldnt want to call fputc for every character in
a megacharacter sequential file! Better to call the C library
routines for writing binary files fwrite and fread.
This assumes you can write an interface that works.
--
...Richard Friedman [rchrd]
Pacific-Sierra Research
2855 Telegraph #415, Berkeley CA 94705
(415) 540 5216
uucp: {ucbvax,lll-lcc,ptsfa,hplabs}!well!rchrd
- or - rchrd@well.uucpmink@cfa.harvard.EDU (Doug Mink) (12/31/86)
In article <407@humu.UUCP>, martin@humu.UUCP (Douglas W. Martin) writes: > Can soneone help me figure out how to write unformatted, > sequential files in F77, such that they do not contain header info? > In PDP-11 Fortran, there existed functions iread and iwrite, with matching > read and write functions in assembly language. It was thus quite easy to > write a file as output from an assembly language program, and later > read that file as input to a Fortran program. How can this be done in F77? I almost never use f77 file i/o anymore, and neither does anyone else I know who does extensive f77 programming. Each f77 programmer has their own toolbox of useful C routines; here's part of the stream i/o portion of mine. The basic features of a f77-callable C subroutine are the underscore after the subroutine name and the addition of string length variables when a character string is passed. Equivalent routines can of course be written for {open(2),read(2),write(2),close(2)}. Enjoy. Doug Mink mink@cfa.harvard.edu {seismo!ihnp4}!harvard!cfa!mink ------------------------------------------------------------------------------ #include <sys/file.h> #include </usr/include/stdio.h> sfopen_ (idev,iflag,path,nc) /* Open UNIX file (Fortran-callable) for buffered I/O using system routines. * * From F77: * * Call SFOPEN (IDEV,IFLAG,PATH) * * Integer*4 IDEV * UNIX file descriptor (returned) (-1 if open failed) * Integer*4 IFLAG * 0 open for reading * 1 create for writing * 2 create for reading and writing at start of file * 3 append: open for writing at end of file, or * create for writing * Character*(*) PATH * Address of null-terminated file name (=path name) * * nc Number of characters in string PATH * * this is not explicitly in the calling argument list; * * Fortran adds string lengths to the end automatically */ char *path; long *iflag; long *idev; int nc; { char *type; FILE *stream; long offset; if (*iflag == 0) type = "r"; if (*iflag == 1) type = "w"; if (*iflag == 2) type = "w+"; if (*iflag == 3) type = "a"; stream = fopen (path,type); if (stream == NULL) *idev = -1; /* set device to -1 if open failed*/ else *idev = (long)stream; return; } sfput_ (idev,nbytes,buf,nwrit) /* Write to UNIX file (Fortran-callable) using buffered I/O. * * From F77: * * Call SFPUT( IDEV,NBYTES,BUF,NWRIT) * * Integer*4 IDEV * UNIX file descriptor (input, returned from SFOPEN) * Integer*4 NBYTES * Number of bytes to write (input) * (Integer,Real) BUF * Address of buffer array (values written to file) * Integer*4 NREAD * Number of bytes written (returned, should=nbytes) */ char *buf; long *nbytes,*nwrit; long *idev; { FILE *stream; int nw,nitems,size; nitems = *nbytes ; size = 1; stream = (FILE*)*idev; nw = fwrite(buf,size,nitems,stream); *nwrit = nw; return; } sfget_ (idev,nbytes,buf,nread) /* Read from UNIX file (Fortran-callable) using buffered I/O. * * From F77: * * Call SFGET (IDEV,NBYTES,BUF,NREAD) * * Integer*4 IDEV * UNIX file descriptor (input, returned from SFOPEN) * Integer*4 NBYTES * Number of bytes to read (input) * (Integer,Real) BUF * Address of buffer array (values returned) * Integer*4 NREAD * Number of bytes read (returned, should=nbytes) */ char *buf; long *nbytes,*nread; long *idev; { FILE *stream; int nr,nitems,size; nitems = *nbytes ; size = 1; stream = (FILE*)*idev; nr = fread(buf,size,nitems,stream); *nread = nr; return; } sfclose_ (idev,ier) /* Close UNIX file opened for buffered I/O (Fortran-callable) * * From F77: * * Call SFCLOSE (IDEV,IER) * * Integer*4 IDEV * UNIX file descriptor (input, returned by SFOPEN) * Integer*4 IER * Error flag (0 => OK) (returned) */ long *idev; long *ier; { FILE *stream; long ptr; stream = (FILE*)*idev; ptr=fclose(stream); *ier=ptr; return; }