Optional date format qualifiers
You can specify optional format qualifiers immediately after the % symbol of the formatting directive.
A date format qualifier defines a field specification
for the date in read or print operations. The following sections describe
what a field specification means for the read and print operations.
For information about display formats, see Display formats.
Tip: The GL_DATETIME environment
variable accepts these date format qualifiers in addition to those
qualifiers that Optional time format qualifiers lists.