https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83282
Bug ID: 83282
Summary: missing comma in format changes output
Product: gcc
Version: 6.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: urbanjost at comcast dot net
Target Milestone: ---
I (accidently) used a GNU/gfortran extension, leaving a comma out
of a format. The output changed unexpectedly. The description of
the extension seems to indicate that the behavior should be the same
whether the comma is present or not. The code produces the following
output
[a ][bb ][ccc ][dddd ]
[a [bb [ccc [dddd
[a [bb [ccc [dddd
The only difference between the three formats is that the first one
has commas between the edit descriptors, some of which are removed in
the other two formats ...
program missing_comma
implicit none
! A missing comma in a format changes output
character(len=*),parameter :: array(*)=[character(len=5) ::
'a','bb','ccc','dddd']
write(*,'(*("[",a,"]":))')array ! with commas
! next, using GNU extension to leave out commas in format
write(*,'(*("[",a"]":))')array
write(*,'(*("["a"]":))')array
end program missing_comma
This is personally a low-priority issue, but might cause significant problems
for pre-f90 code where the lack of commas in format descriptors is common.
