Open Watcom FORTRAN 77 Language Reference
Open Watcom FORTRAN 77 Language Reference
Open Watcom FORTRAN 77 Language Reference
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<strong>Language</strong> <strong>Reference</strong><br />
5. Any character expression except one involving the concatenation of an operand<br />
whose length specification is (*) unless the operand is a symbolic constant (see<br />
the PARAMETER statement).<br />
6. An asterisk (*), indicating list-directed formatting.<br />
7. A NAMELIST name, indicating namelist-directed formatting.<br />
If the optional FMT= specifier is omitted then the format specifier must be the second item in the list of<br />
specifiers and UNIT= must not be specified for the first item in the list.<br />
10.6.3 Record Specifier<br />
The form of a record specifier in an input/output statement is:<br />
REC = rn<br />
rn is an integer expression whose value must be positive. It is the number of the record to<br />
be read when a file is connected for direct access.<br />
10.6.4 Input/Output Status Specifier<br />
The form of an input/output status specifier in an input/output statement is:<br />
IOSTAT = ios ios is an integer variable or integer array element. It is defined with zero if no error<br />
occurs, a positive integer value if an error occurs, or a negative integer value if an<br />
end-of-file occurs.<br />
If an input/output error or end-of-file condition occurs during the execution of an input/output statement<br />
and the input/output status specifier is present then execution of the program is not terminated.<br />
Input/output errors may result from a violation of the rules of <strong>FORTRAN</strong> or from a file system error. For<br />
example, a negative unit number will result in an error since this is a violation of the rules of <strong>FORTRAN</strong>.<br />
An example of a file system error might be an attempt to create a file on a non-existent file storage device.<br />
Consult the User’s Guide for a list of <strong>Open</strong> <strong>Watcom</strong> <strong>FORTRAN</strong> <strong>77</strong> diagnostic messages. An input/output<br />
status of nn corresponds to the message IO-nn. For example, if the status returned is 3 then the error is:<br />
IO-03 ENDFILE statement requires sequential access mode<br />
10.6.5 Error Specifier<br />
The form of an error specifier in an input/output statement is:<br />
ERR = s<br />
s is a statement label. When an error occurs, execution is transferred to the statement<br />
labelled by s.<br />
If an input/output error occurs during the execution of an input/output statement and the ERR= specifier is<br />
present then execution of the program is not terminated.<br />
222 Specifiers
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