| <Syntax> |
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[ UNIT = ] io_unit
| io-unit | ::= | expression |
| | | variable |
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The UNIT= specifier is permitted in any input/output statement,
except for PRINT, and for INQUIRE with FILE=.
The keyword and equals sign may be omitted if and only if it is the
first specifier in the statement.
If io-unit is an expression, it must be a scalar integer
expression and must be
non-negative, or the value of one
of the constants ERROR_UNIT, INPUT_UNIT or OUTPUT_UNIT from the
intrinsic module ISO_FORTRAN_ENV.
If io-unit is a variable, it must be a character variable
but may be either a scalar or an array;
this form is only permitted in READ and WRITE statements.
The asterisk form of io-unit is also permitted only in READ
and WRITE statements.
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| <Semantics> |
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Identifies the logical unit
which is the subject of the input/output statement.
An io-unit that is an expression identifies an external
unit; an io-unit that is a variable identifies an internal
unit, and an io-unit that is an asterisk identifies the
external unit INPUT_UNIT in a READ statement or the external unit
OUTPUT_UNIT in a WRITE statement.
If io-unit is a scalar character variable, the internal unit
contains only one record; if it is an array variable, the internal
unit has a number of records equal to the number of elements of the
array. In each case the length of each record is the character
length of the variable.
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| <Related> |
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BACKSPACE statement,
CLOSE statement,
ENDFILE statement,
INQUIRE statement,
OPEN statement,
READ statement,
REWIND statement,
WRITE statement |
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