Implementation:Alibaba MNN RapidJSON Inttypes

Knowledge Sources	Alibaba_MNN RapidJSON
Domains	JSON_Parsing, Compatibility
Last Updated	2026-02-10 12:00 GMT

Overview

3rd_party/rapidjson/msinttypes/inttypes.h (316 lines) provides an ISO C99-compliant <inttypes.h> implementation for older Microsoft Visual C++ compilers that lack native support. This vendored header enables RapidJSON (and by extension Alibaba MNN) to use standard integer formatting macros (PRId64, PRIu32, etc.) across all supported Windows compiler versions.

Usage note: Vendored dependency used internally by MNN for JSON configuration parsing (model configs, LLM configs). Not directly imported by end users.

Purpose

Prior to Visual Studio 2013 (MSVC 1800), the <inttypes.h> header was not provided by the compiler. This header fills that gap by defining:

Format conversion macros for printf and scanf families
The imaxdiv_t type for integer division results
The imaxabs() and imaxdiv() functions

Conditional Compilation

The header is guarded to only activate on MSVC:

#ifndef _MSC_VER
#error "Use this header only with Microsoft Visual C++ compilers!"
#endif

// For MSVC >= 2013, defer to the native <inttypes.h>
#if _MSC_VER >= 1800
#include <inttypes.h>
#else
// ... provide compatibility definitions ...
#endif

Defined Macros

The header defines format specifier macros for the following integer types in groups for printf and scanf:

Category	Example Macros
Signed decimal	`PRId8`, `PRId16`, `PRId32`, `PRId64`
Unsigned decimal	`PRIu8`, `PRIu16`, `PRIu32`, `PRIu64`
Unsigned hex	`PRIx8`, `PRIx16`, `PRIx32`, `PRIx64`
Unsigned octal	`PRIo8`, `PRIo16`, `PRIo32`, `PRIo64`
`intmax_t` types	`PRIdMAX`, `PRIuMAX`, `PRIxMAX`
Pointer types	`PRIdPTR`, `PRIuPTR`, `PRIxPTR`
scanf variants	`SCNd8`, `SCNd16`, `SCNd32`, `SCNd64`, etc.

Key Types and Functions

typedef struct {
    intmax_t quot;
    intmax_t rem;
} imaxdiv_t;

intmax_t imaxabs(intmax_t value);
imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
intmax_t strtoimax(const char* nptr, char** endptr, int base);
uintmax_t strtoumax(const char* nptr, char** endptr, int base);

Dependencies

Includes the companion header msinttypes/stdint.h for the base integer type definitions.

License

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