struct.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)struct.1	8.1	9/11/90
.TH struct 1 VAX "" Unsupported
.SH Name
struct \- structure FORTRAN programs
.SH Syntax
.B struct
[ \fIoptions\fP ] ...
\fIfile\fP
.SH Description
The 
.PN struct
command translates the FORTRAN program specified by
.I file
(standard input default)
into a 
.PN ratfor 
program.
Wherever possible, 
.PN ratfor 
control constructs
replace the original FORTRAN.
Statement numbers appear only where still necessary.
Cosmetic changes are made, including changing Hollerith strings
into quoted strings
and relational operators into symbols (for example, ".GT." into ">").
The output is appropriately indented.
.SH Options
.TP
.B  \-s
Input is accepted in standard format, that is
comments are specified by a c, C, or * in column 1, and continuation lines
are specified by a nonzero, nonblank character in column 6.
Normally input is in the form accepted by 
.MS f77 1 .
.TP
.B  \-i
Do not turn computed goto statements into
switches.
.Pn ( ratfor 
does not turn switches back
into computed goto statements.)
.TP
.B  \-a
Turn sequences of else ifs into a
. Pn non- ratfor 
switch of the form
.IP
.nf
.ta 5 7
\f(CWswitch
	{	case pred1: code
		case pred2: code
		case pred3: code
		default: code
	}\fP
.fi
.DT
.IP
The case predicates are tested in order;
the code appropriate to only one case is executed.
This generalized form of switch statement does not
occur in 
.PN ratfor .
.TP
.B  \-b
Generate goto's instead of multilevel break statements.
.TP
.B  \-n
Generate goto's instead of multilevel next statements.
.TP
.BI \-t n
Make
the nonzero integer
.I n
the lowest valued label in the output program
(default 10).
.TP
.BI \-c n
Increment successive labels
in the output program
by the nonzero integer
.I n
(default 1).
.TP
.BI \-e n
If 
.I n
is 0 (default),
place code within a loop only if it can
lead to an iteration of the loop.
If
.I n
is nonzero,
admit a small code segments to a loop
if otherwise the loop would have exits to several places including the segment,
and the segment can be reached only from the loop.
`Small' is close to, but not equal to, the
number of statements in the code segment.
Values of n under 10 are suggested.
.SH Restrictions
Struct knows FORTRAN 66 syntax, but not full FORTRAN 77.
.br
If an input FORTRAN program contains identifiers which
are reserved words in 
.PN ratfor , 
the structured
version of the program
will not be a valid 
.PN ratfor 
program.
.br
The labels generated cannot go above 32767.
.br
If you get a goto without a target, try
.B \-e .
.SH Files
/tmp/struct*
.br
/usr/lib/struct/*
.SH See Also
f77(1)