Constant is too large for long long

Introduction

I get the message:

Warning[Pe1297]: constant is too large for long long; given unsigned long long type (nonstandard)

.. when using the decimal constant 2147483648.

Possible solutions

• Use suffix (e.g., 2147483648UL)
• Use octal or hexadecimal representation instead (e.g., 0x80000000)
• Combine constants that are not too large, e.g., use LONG_MIN defined as

• #define LONG_MIN (-2147483647-1)

Background

The standard says the type of a decimal constant without suffix shall be the first that matches in the following list:

int, long int, long long int

The constant 2147483648 (= 0x8000 0000) does not fit in a long long int.

The compiler handles this by using unsigned long long int for the constant, and gives an appropriate warning.

Note

Type casts, e.g.,

/*...*/ (unsigned long long) 2147483648; /*...*/

are not applied until after the constant has a type. See also Technical Note 60149.

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