Intel® Fortran Compiler 16.0 User and Reference Guide
The X edit descriptor specifies a character position to the right of the current position in an I/O record. It takes the following form:
nX
The n is a positive integer literal constant (with no kind parameter) indicating the nth character position to the right of the current character.
On output, the X edit descriptor does not output any characters when it appears at the end of a format specification; for example:
WRITE (6,99) K
99 FORMAT ('^K=',I6,5X)
Note that the symbol ^ represents a nonprinting blank character. This example writes a record of only 9 characters. To cause n trailing blanks to be output at the end of a record, specify a format of n('^').