| Issue |
151465
|
| Summary |
[Flang] reads d* prefixed strings as floating-point values
|
| Labels |
flang
|
| Assignees |
|
| Reporter |
marikurz-amd
|
Trying to read a (non-real) string into a `real` variable unexpectedly succeeds instead of throwing an error if both
- the string starts with `d` or `e`,
- _and_ a floating-point format identifier without explicit width is used.
This behavior can be reproduced with
```
Flang Version: 21.0.0git commit 532facc78e
```
and the following snippet:
```fortran
program reproducer
implicit none
character(len=4) :: str = "dstr"
real :: test
integer :: istat
read(str,"(D)", iostat=istat) test
WRITE(*,*) "Is the string real? ", (istat .EQ. 0)
end program reproducer
```
which yields
```
Is the string real? T
```
Thus, flang compiles and succeeds in reading the string `"dstr"` into a `real` variable, which should not be allowed. If an explicit width is used, such as `"(D4.0)"`, Flang throws `istat != 0` as expected.
In my opinion, the expected behavior would be one of the following:
1. Flang should throw a compile-time error as no standard-conform, explicit field width in the format `"(Dw.d)"` is provided. This is how `gfortran` behaves.
2. Flang should correctly detect during runtime that the string cannot be transformed into a `real` in a meaningful way and provide `iostat != 0`. This is the behavior of Classic-Flang and the Cray compiler.
I would speculate this behavior is somehow caused by `d` and `e` are valid components of a floating-point number in exponential format.
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