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long long data type in C99 and C90

C99 supports the integral data type long long.

This type is 64 bits wide in the ARM compilation tools.

For example:

long long int j = 25902068371200;                // length of light
                                                 // day, meters
unsigned long long int i = 94607304725808000ULL; // length of light
                                                 // year, meters

long long is also available in C90 when not using --strict.

__int64 is a synonym for long long. __int64 is always available.