# Long Long integers

This chapter describes the global functions you use to perform 64-bit
integer operations. The functions define a portable API that can be used
reliably in any environment. Where 64-bit integers are desired, use of
NSPR's implementation is recommended to ensure cross-platform
compatibility.

Most of the 64-bit integer operations are implemented as macros. The
specific implementation of each macro depends on whether the compiler
for the target platform supports 64-bit integers. For a specific target
platform, if 64-bit integers are supported for that platform, define
`HAVE_LONG_LONG` at compile time.

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## 64-Bit Integer Types

NSPR provides two types to represent 64-bit integers:

- {ref}`PRInt64`
- {ref}`PRUint64`

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## 64-Bit Integer Functions

The API defined for the 64-bit integer functions is consistent across
all supported platforms.