The Standard C++ Library describes a specific type by providing a specialization of the numeric_limits template for the type. Static member functions and static constant data members then provide information specific to the type. The Standard C++ Library includes descriptions of the fundamental datatypes given in Table 20.
| bool | char | int | float |
signed char | short | double | |
unsigned char | long | long double | |
wchar_t | |||
unsigned short | |||
unsigned int | |||
unsigned long |
Certain implementations may also provide information on other datatypes. Whether or not an implementation is described can be discovered using the static data member is_specialized. For example, the following is legal, and will indicate that the string datatype is not described by this mechanism.
std::cout << "are strings described " << std::numeric_limits<string>::is_specialized << std::endl;
For datatypes that do not have a specialization, the values yielded by the functions and data members in numeric_limits are generally zero or false.
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Licensed under the Apache License, Version 2.0.
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