From Jason Turner

[diff.cpp03.input.output]

C++17 → C++20 3.3 KB 45 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmp72lefblq/{from.md → to.md} +20 -22
tmp/tmp72lefblq/{from.md → to.md} RENAMED
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- ### Clause [[input.output]]: input/output library <a id="diff.cpp03.input.output">[[diff.cpp03.input.output]]</a>
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- [[istream::sentry]], [[ostream::sentry]], [[iostate.flags]] **Change:**
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- Specify use of `explicit` in existing boolean conversion functions.
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- **Rationale:** Clarify intentions, avoid workarounds. **Effect on
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- original feature:** Valid C++03code that relies on implicit boolean
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- conversions will fail to compile with this International Standard. Such
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- conversions occur in the following conditions:
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  - passing a value to a function that takes an argument of type `bool`;
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  - using `operator==` to compare to `false` or `true`;
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  - returning a value from a function with a return type of `bool`;
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  - initializing members of type `bool` via aggregate initialization;
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- - initializing a `const bool&` which would bind to a temporary.
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- [[ios::failure]] **Change:** Change base class of
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- `std::ios_base::failure`. **Rationale:** More detailed error messages.
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- **Effect on original feature:** `std::ios_base::failure` is no longer
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- derived directly from `std::exception`, but is now derived from
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- `std::system_error`, which in turn is derived from `std::runtime_error`.
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- Valid C++03code that assumes that `std::ios_base::failure` is derived
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- directly from `std::exception` may execute differently in this
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- International Standard.
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- [[ios.base]] **Change:** Flag types in `std::ios_base` are now bitmasks
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- with values defined as constexpr static members. **Rationale:** Required
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- for new features. **Effect on original feature:** Valid C++03code that
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- relies on `std::ios_base` flag types being represented as `std::bitset`
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- or as an integer type may fail to compile with this International
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- Standard. For example:
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  ``` cpp
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  #include <iostream>
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  int main() {
 
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+ ### [[input.output]]: input/output library <a id="diff.cpp03.input.output">[[diff.cpp03.input.output]]</a>
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+ **Change:** Specify use of `explicit` in existing boolean conversion
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+ functions. **Rationale:** Clarify intentions, avoid workarounds.
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+ **Effect on original feature:** Valid C++03 code that relies on implicit
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+ boolean conversions will fail to compile with this International
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+ Standard. Such conversions occur in the following conditions:
 
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  - passing a value to a function that takes an argument of type `bool`;
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  - using `operator==` to compare to `false` or `true`;
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  - returning a value from a function with a return type of `bool`;
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  - initializing members of type `bool` via aggregate initialization;
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+ - initializing a `const bool&` which would bind to a temporary object.
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+ **Change:** Change base class of `std::ios_base::failure`.
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+ **Rationale:** More detailed error messages. **Effect on original
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+ feature:** `std::ios_base::failure` is no longer derived directly from
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+ `std::exception`, but is now derived from `std::system_error`, which in
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+ turn is derived from `std::runtime_error`. Valid C++03 code that assumes
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+ that `std::ios_base::failure` is derived directly from `std::exception`
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+ may execute differently in this International Standard.
 
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+ **Change:** Flag types in `std::ios_base` are now bitmasks with values
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+ defined as constexpr static members. **Rationale:** Required for new
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+ features. **Effect on original feature:** Valid C++03 code that relies
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+ on `std::ios_base` flag types being represented as `std::bitset` or as
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+ an integer type may fail to compile with this International Standard.
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+ For example:
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  ``` cpp
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  #include <iostream>
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  int main() {