Open Watcom FORTRAN 77 Language Reference

Language Reference
REC = rn
IOSTAT = ios
ERR = s
rn is an integer expression whose value must be positive. It is the number of the record to
be written when a file is connected for direct access.
is an input/output status specifier. The integer variable or integer array element ios is
defined with zero if no error condition occurs or a positive integer value if an error
condition occurs.
is an error specifier and s is a statement label. When an error occurs, execution is
transferred to the statement labelled by s.
Output list - An output list may contain one or more of the following:
1. A variable name.
2. An array element name.
3. A character substring name.
4. An array name except an assumed-size dummy array.
5. Any other expression except a character expression involving concatenation of an operand
whose length specification is an asterisk in parentheses unless the operand is the symbolic name
of a constant (since the length can be determined at compile time).
6. An implied-DO list of the form:
( dlist, i = e1, e2 [,e3] )
where dlist is composed of one or more of items (1) through (6).
Example:
WRITE( 6, 100 )X, Y, Z
WRITE( UNIT=6, FMT=100 )X, Y, Z
100 FORMAT( 3F10.5 )
WRITE( UNIT=6, FMT=’( 3F10.5 )’ )X, Y, Z
WRITE( 6, ’( 3F10.5 )’ )X, Y, Z
The above gives four examples of formatted WRITE statements. In all cases, the format conversion is
identical but it was specified in different ways. When executed, the effect of all WRITE statements is the
same. The unit number, used here, is 6. There are, in fact, many other ways in which the WRITE statement
could have been written, all of which would have the same effect when executed. We have not shown use
of all the specifiers.
Example:
WRITE( 6, * )X, Y, Z
WRITE( *, * )X, Y, Z
WRITE( UNIT=6, FMT=* )X, Y, Z
WRITE( UNIT=*, FMT=* )X, Y, Z
The above four examples of list-directed formatted output are all equivalent. Open Watcom FORTRAN 77
assumes unit 6 when the unit number identifier is an asterisk (as in the second and fourth examples). In the
examples, the format identifier is an asterisk indicating list-directed formatting.
148 WRITE Statement