User and Reference Guide for the Intel® Fortran Compiler 14.0
The following rules apply to defined I/O data transfers:
During execution of a defined I/O procedure, there must be no I/O for an external unit except for the unit argument. However, I/O is permitted for internal files.
You cannot use user-defined I/O in combination with asynchronous I/O.
No file-positioning commands are permitted in the defined I/O procedure. OPEN, CLOSE, BACKSPACE, ENDFILE, and REWIND statements will not be executed. Any ADVANCE= specifier in a child statement is ignored.
A record positioning edit descriptor, such as TL and TR, used on the unit by a child data transfer statement will not cause the record position to be positioned before the record position at the time the defined I/O procedure was invoked.
A child data transfer statement must not specify the ID=, POS=, or REC= specifier in an I/O control list.
The file position on entry is treated as a left tab limit and there is no record termination on return. However, a child statement with slash (/) edit descriptor, or explicit record termination by a list-directed child I/O, is allowed.
If the unit is associated with an external file (for example, non-negative, or equal to one of the constants ERROR_UNIT, INPUT_UNIT or OUTPUT_UNIT from the intrinsic module ISO_FORTRAN_ENV), the current settings for the pad mode, sign mode, etc., can be discovered by using INQUIRE with PAD=, SIGN=, etc. on the unit argument.
Note that INQUIRE must not be used if the unit is associated with an internal file. When an internal unit is used with the INQUIRE statement, an error condition will occur, and any variable specified in an IOSTAT= specifier in the INQUIRE statement will be assigned the value IOSTAT_INQUIRE_INTERNAL_UNIT from the intrinsic module ISO_FORTRAN_ENV.