cpp/io/basic istream/operator gtgt

Extracts values from an input stream.

@1-11@ Extracts a value potentially skipping preceding whitespace. The value is stored to a given reference.

@@ This function behaves as a. After constructing and checking the sentry object, which may skip leading whitespace, extracts a value by calling.

@12@ Extracts a value potentially skipping preceding whitespace. The value is stored to a given reference.

@@ This function behaves as a. After constructing and checking the sentry object, which may skip leading whitespace, extracts a value  by calling. After that:
 * If, sets and stores  to.
 * Otherwise, if, sets and stores  to.
 * Otherwise, stores to.

@13@ Extracts an value potentially skipping preceding whitespace. The value is stored to a given reference.

@@ This function behaves as a. After constructing and checking the sentry object, which may skip leading whitespace, extracts a value  by calling. After that:
 * If, sets and stores  to.
 * Otherwise, if, sets and stores  to.
 * Otherwise, stores to.

@14@ Extracts an extended floating-point value potentially skipping preceding whitespace. The value is stored to a given reference. The library provides overloads for all cv-unqualified extended floating-point types as the referenced type of the parameter.

@@ Determines the standard floating-point type as follows:
 * If the floating-point conversion rank of is less than or equal to that of, then  is.
 * Otherwise, if the floating-point conversion rank of is less than or equal to that of, then  is.
 * Otherwise, is.

@@ This function behaves as a. After constructing and checking the sentry object, which may skip leading whitespace, extracts an value  by calling. After that:
 * If, sets and stores  to.
 * Otherwise, if, sets and stores  to.
 * Otherwise, stores to.

@15-17@ Calls, where is an I/O manipulator.

@18@ Behaves as an. After constructing and checking the sentry object, extracts all data from and stores it to. The extraction stops if one of the following conditions are met:
 * end-of-file occurs on the input sequence;
 * inserting in the output sequence fails (in which case the character to be inserted is not extracted);
 * an exception occurs (in which case the exception is caught, and only rethrown if it inserted no characters and is enabled in ).

In either case, stores the number of characters extracted in the member variable accessed by subsequent calls to gcount. If is a null pointer or if no characters were inserted into, calls  (which may throw std if enabled).

If extraction fails (e.g. if a letter was entered where a digit is expected), zero is written to and  is set. For signed integers, if extraction results in the value too large or too small to fit in, or  (respectively) is written and  flag is set. For unsigned integers, if extraction results in the value too large or too small to fit in, is written and  flag is set.

Return value
@1-16,18@ @17@