balazske marked 2 inline comments as done.
balazske added a comment.
The intent is to model the fread-fwrite function failure by returning the error
value and set the stream into error state. The error state is a composite of
**ferror** and **feof**. The questions are now, at what case do these functions
fail and with what error type?
================
Comment at: clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp:107
+ /// This value applies to all execution paths in ErrorState except the FEOF
+ /// case. In more detail, an EOF+indeterminate state is the same as EOF
state.
+ bool FilePositionIndeterminate = false;
----------------
Szelethus wrote:
> The standard suggests that this happens on FERROR, not FEOF.
>
> > If an error occurs, the resulting value of the file position indicator for
> > the stream is indeterminate. If a partial element is read, its value is
> > indeterminate.
>
> It would be wild if the stream wouldn't set the FEOF flag after reaching the
> end of the file. Also, I would imagine FEOF being usually implemented with
> the file position indicator.
>
> ```lang=bash
> $ cat test.cpp`
> ```
> ```lang=cpp
> #include "stdio.h"
>
> int main() {
> FILE *F = fopen("test.cpp", "r");
> char Buf[1024];
> const int READ_COUNT = 99999;
> if (READ_COUNT != fread(Buf, sizeof(char), READ_COUNT, F)) {
> printf("%i\n", feof(F));
> }
> }
> ```
> ```lang=bash
> $ build/bin/clang++ test.cpp && ./a.out
> 1
>
> ```
>
> Operations on an EOF and indeterminate stream are very different.
I wanted to say in that comment that `FilePositionIndeterminate` should be
ignored if the `ErrorState` is `ErrorFEof`. In other words the file is never
indeterminate if in EOF state.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D78374/new/
https://reviews.llvm.org/D78374
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