http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46641
Summary: Specification-expr checks and results with C_SIZEOF
and SIZEOF
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Keywords: wrong-code
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: bur...@gcc.gnu.org
Kind of follow up to PR 46638; based on
http://groups.google.com/group/comp.lang.fortran/browse_thread/thread/1b907e3b7b6f3461
There is something fishy about the following program. In terms of validity, the
question is whether
C_SIZEOF (structure-constructor ())
is a valid initialization expression -- gfortran accepts it.
Besides the validity issue, there is something fishy. The "string" has a length
of 16 -- using either C_SIZEOF or the literal 16 in the declaration. However,
if one uses the literal, it works while using C_SIZEOF the TRANSFER seems to
override some memory it shouldn't - causing a segfault.
Using "sizeof()" instead of "c_sizeof()", the either version is rejected by the
Cray compiler - but both version work with ifort. Neither compiler likes the
C_sizeof version (not implemented in Cray, not sure about ifort).
gfortran prints for sizeof the error "must have constant character length" for
both versions.
module utils
use ISO_C_BINDING
implicit none
type, bind(C) :: CPUID_type
integer(C_INT32_T) eax
integer(C_INT32_T) ebx
integer(C_INT32_T) edx
integer(C_INT32_T) ecx
end type CPUID_type
type(CPUID_type) :: test_type
end module utils
program mxcsr_test
use ISO_C_BINDING
use utils
implicit none
integer(C_INT32_T) reg
integer(C_INT64_T) ts1, ts2
integer(C_INT16_T) sw, cw
integer(C_INT32_T) eax, ecx
type(CPUID_type) result
! Works:
! character(16) string
! Compiles but fails:
character(SIZEOF(CPUID_type(0,0,0,0))) string
! Rejected with: must have constant character length
! character(SIZEOF(test_type)) string
result = CPUID_TYPE(int(Z'0000000A'),int(Z'756E6547'), &
int(Z'49656E69'),int(Z'6C65746E'))
print *, len(string) ! OK: 16
string = transfer(result,string)
write(*,'(a,a)') 'Brand name: ',string(5:16)
write(*,'(4(z8.8:1x))') result
end program mxcsr_test
