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From: guy@rlgvax.UUCP (Guy Harris)
Newsgroups: net.lang
Subject: Re: Slow Fortran I/O
Message-ID: <2078@rlgvax.UUCP>
Date: Thu, 5-Jul-84 17:39:13 EDT
Article-I.D.: rlgvax.2078
Posted: Thu Jul  5 17:39:13 1984
Date-Received: Sat, 7-Jul-84 07:11:25 EDT
References: <9625@lanl-a.UUCP> <5884@mcvax.UUCP>
Organization: CCI Office Systems Group, Reston, VA
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> I'm not sure about this. Surely interpreting formats at runtime slows I/O a
> lot. It could be possible to compile the formats, but Fortran also allows
> you to read the format at run-time, so you still need your format
> interpreter around. Does any Fortran compiler compile formats?

Yes - the RT-11 Fortran compiler, about which the complaint of slow Fortran
I/O was originally made.  I suspect the VMS compiler also does so.  There
seem to be two philosophies about this - the compilers which directly
interpret the string at run time (of which there are several, including
Stu Feldman's UNIX "f77" compiler, upon which the Berkeley compiler is
based) and the compilers which compile it first (of which there are several,
including DEC's compilers).  In the latter case, you can include the format
compiler as part of the Fortran I/O library, only referencing it if the
format is actually specified at run-time.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy