18 Diagnostics library [diagnostics]

18.2 Exception classes [std.exceptions]

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The C++ standard library provides classes to be used to report certain errors ([res.on.exception.handling]) in C++ programs.
In the error model reflected in these classes, errors are divided into two broad categories: logic errors and runtime errors.
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The distinguishing characteristic of logic errors is that they are due to errors in the internal logic of the program.
In theory, they are preventable.
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By contrast, runtime errors are due to events beyond the scope of the program.
They cannot be easily predicted in advance.
The header <stdexcept> defines several types of predefined exceptions for reporting errors in a C++ program.
These exceptions are related by inheritance.

18.2.1 Header <stdexcept> synopsis [stdexcept.syn]

namespace std {
  class logic_error;
    class domain_error;
    class invalid_argument;
    class length_error;
    class out_of_range;
  class runtime_error;
    class range_error;
    class overflow_error;
    class underflow_error;
}

18.2.2 Class logic_­error [logic.error]

namespace std {
  class logic_error : public exception {
  public:
    explicit logic_error(const string& what_arg);
    explicit logic_error(const char* what_arg);
  };
}
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The class logic_­error defines the type of objects thrown as exceptions to report errors presumably detectable before the program executes, such as violations of logical preconditions or class invariants.
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logic_error(const string& what_arg);
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Effects: Constructs an object of class logic_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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logic_error(const char* what_arg);
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Effects: Constructs an object of class logic_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.3 Class domain_­error [domain.error]

namespace std {
  class domain_error : public logic_error {
  public:
    explicit domain_error(const string& what_arg);
    explicit domain_error(const char* what_arg);
  };
}
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The class domain_­error defines the type of objects thrown as exceptions by the implementation to report domain errors.
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domain_error(const string& what_arg);
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Effects: Constructs an object of class domain_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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domain_error(const char* what_arg);
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Effects: Constructs an object of class domain_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.4 Class invalid_­argument [invalid.argument]

namespace std {
  class invalid_argument : public logic_error {
  public:
    explicit invalid_argument(const string& what_arg);
    explicit invalid_argument(const char* what_arg);
  };
}
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The class invalid_­argument defines the type of objects thrown as exceptions to report an invalid argument.
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invalid_argument(const string& what_arg);
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Effects: Constructs an object of class invalid_­argument.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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invalid_argument(const char* what_arg);
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Effects: Constructs an object of class invalid_­argument.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.5 Class length_­error [length.error]

namespace std {
  class length_error : public logic_error {
  public:
    explicit length_error(const string& what_arg);
    explicit length_error(const char* what_arg);
  };
}
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The class length_­error defines the type of objects thrown as exceptions to report an attempt to produce an object whose length exceeds its maximum allowable size.
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length_error(const string& what_arg);
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Effects: Constructs an object of class length_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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length_error(const char* what_arg);
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Effects: Constructs an object of class length_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.6 Class out_­of_­range [out.of.range]

namespace std {
  class out_of_range : public logic_error {
  public:
    explicit out_of_range(const string& what_arg);
    explicit out_of_range(const char* what_arg);
  };
}
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The class out_­of_­range defines the type of objects thrown as exceptions to report an argument value not in its expected range.
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out_of_range(const string& what_arg);
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Effects: Constructs an object of class out_­of_­range.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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out_of_range(const char* what_arg);
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Effects: Constructs an object of class out_­of_­range.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.7 Class runtime_­error [runtime.error]

namespace std {
  class runtime_error : public exception {
  public:
    explicit runtime_error(const string& what_arg);
    explicit runtime_error(const char* what_arg);
  };
}
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The class runtime_­error defines the type of objects thrown as exceptions to report errors presumably detectable only when the program executes.
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runtime_error(const string& what_arg);
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Effects: Constructs an object of class runtime_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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runtime_error(const char* what_arg);
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Effects: Constructs an object of class runtime_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.8 Class range_­error [range.error]

namespace std {
  class range_error : public runtime_error {
  public:
    explicit range_error(const string& what_arg);
    explicit range_error(const char* what_arg);
  };
}
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The class range_­error defines the type of objects thrown as exceptions to report range errors in internal computations.
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range_error(const string& what_arg);
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Effects: Constructs an object of class range_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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range_error(const char* what_arg);
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Effects: Constructs an object of class range_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.9 Class overflow_­error [overflow.error]

namespace std {
  class overflow_error : public runtime_error {
  public:
    explicit overflow_error(const string& what_arg);
    explicit overflow_error(const char* what_arg);
  };
}
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The class overflow_­error defines the type of objects thrown as exceptions to report an arithmetic overflow error.
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overflow_error(const string& what_arg);
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Effects: Constructs an object of class overflow_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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overflow_error(const char* what_arg);
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Effects: Constructs an object of class overflow_­error.
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Ensures: strcmp(what(), what_­arg) == 0.

18.2.10 Class underflow_­error [underflow.error]

namespace std {
  class underflow_error : public runtime_error {
  public:
    explicit underflow_error(const string& what_arg);
    explicit underflow_error(const char* what_arg);
  };
}
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The class underflow_­error defines the type of objects thrown as exceptions to report an arithmetic underflow error.
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underflow_error(const string& what_arg);
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Effects: Constructs an object of class underflow_­error.
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Ensures: strcmp(what(), what_­arg.c_­str()) == 0.
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underflow_error(const char* what_arg);
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Effects: Constructs an object of class underflow_­error.
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Ensures: strcmp(what(), what_­arg) == 0.