READ Statement

Syntax (not all the specifiers can be used at the same time,)

 
READ([UNIT=]< unit >, [FMT=]< format >, IOSTAT=< int-variable >, ERR=< label >, &

		 END=< label >, EOR=< label >, ADVANCE=< advance-mode >, REC=< int-expr >, &

		 SIZE=< num-chars >) < output-list > 

where

• UNIT=< unit > is a valid logical unit number or * for the default (standard) output, if it is the first field then the specifier is optional.
• FMT=< format > is a string of formatting characters, a valid FORMAT statement label or a * for free format. If this is the second field then the specifier is optional.
• IOSTAT=< int-variable > specifies an integer variable to hold a return code, as usual, zero means no error.
• < label > in ERR= is a valid label to where control jumps if there is a read error.
• < label > in END= is a valid label to where control jumps if an end-of-file is encountered, this can only be present in a READ statement.
• < advance-mode > specifies whether each READ should start a new record or not, setting the specifier to 'NO' initiates non-advancing I/O. The default is 'YES'. If non-advancing I/O is used then the file must be connected for sequential access and the format must be explicitly stated.
• EOR will jump to the specified label if an end-of-record is encountered. This can only be present in a READ statement and only if ADVANCE='NO' is also present.
• REC=< int-expr > is the record number for direct access.
• the SIZE specifier is used in conjunction with an integer variable, in this case nch. The variable will hold the number of characters read. This can only be present in a READ statement and only if ADVANCE='NO' is also present.

Consider,

    READ(14,FMT='(3(F10.7,1x))',REC=iexp) a,b,c

here, the record specified by the integer iexp is read -- this record should contain 3 real numbers separated by a space with 10 column and 7 decimal places. The values will be placed in a, b and c.

  READ(*,'(A)',ADVANCE='NO',EOR=12,SIZE=nch) str

Since non-advancing output has been specified, the cursor will remain on the same line as the string is read. Under normal circumstances (default advancing output) the cursor would be positioned at the start of the next line. Note the explicit format descriptor. SIZE reurns the length of the string and EOR= specifies an destination if an end-of-record is encountered.

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