cherry pick runtime I/O fixes for namelist array input, backspace, rewind #947
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When a WRITE overwrites an endfile record, we need to forget that there was an endfile record. When doing a BACKSPACE after an explicit ENDFILE statement, the position afterwards must be upon the endfile record. Attempts to join list-directed delimited character input across record boundaries was due to a bad reading of the standard and has been deleted, now that the requirements are better understood. This problem would cause a read attempt past EOF if a delimited character input value was at the end of a record. It turns out that delimited list-directed (and NAMELIST) character output is required to emit contiguous doubled instances of the delimiter character when it appears in the output value. When fixed-size records are being emitted, as is the case with internal output, this is not possible when the problematic character falls on the last position of a record. No two other Fortran compilers do the same thing in this situation so there is no good precedent to follow. Because it seems least wrong, with this patch we now emit one copy of the delimiter as the last character of the current record and another as the first character of the next record. (The second-least-wrong alternative might be to flag a runtime error, but that seems harsh since it's not an explicit error in the standard, and the output may not have to be usable later as input anyway.) Consequently, the output is not suitable for use as list-directed or NAMELIST input. If a later standard were to clarify this case, this behavior will of course change as needed to conform. Differential Revision: https://reviews.llvm.org/D106695
NAMELIST I/O formatting uses the runtime infrastructure for list-directed I/O. List-directed input processing has same state that requires reinitialization for each successive NAMELIST input item. This patch fixes bugs with "null" items and repetition counts on NAMELIST input items after the first in the group. Differential Revision: https://reviews.llvm.org/D106694
vdonaldson
requested review from
jeanPerier,
mleair,
schweitzpgi,
klausler and
psteinfeld
|
LGTM, of course. But I don't have authority to approve. |
psteinfeld
approved these changes
Jul 28, 2021
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.