http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56675
Bug #: 56675
Summary: I/O: Check edit descriptors with READ/WRITE used in
FORMAT statements
Classification: Unclassified
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: bur...@gcc.gnu.org
https://groups.google.com/forum/#!topic/comp.lang.fortran/BxWaYSkmV2w
The following code shows that the special checks for READ/WRITE/PRINT do not
get checked for with FORMAT but only with a string.
Seemingly, the format is checked when FORMAT is encountered - one should
consider to do additionally a check if READ/WRITE/PRINT is used.
[The latter becomes even more useful when looking at the types of the arguments
(e.g. "a" edit descriptor with a "real" expression/variable). However,
currently this is only checked at run time. For compile time, it should be
doable if the I/O list doesn't contain nonconst-shape arrays and no
io-do-lists.]
implicit none
integer :: z
! OK: Diagnosed. (Side note: Also diagnosed by NAG.)
! character(len=*), parameter :: str = '(i0)'
! read (*,str) z ! Positive width required in format string
! read (*,"(i0)") z ! "Positive width required in format string"
! Not diagnosed but diagnosable. (Also not diagnosed by NAG.)
read (*, 99) z ! 'Wrongly' accepted (at compile time)
99 FORMAT (i0) ! (gives error at run time)
! RFC: Validly rejected or not? (Note: Also rejected by NAG)
! read (*, 100) z ! Rejected at run time (but not used;
! 100 FORMAT (i2,i0)! may it reject it or not?)
end
