Integer Input Scanning

Defines macros for converting formatted text to integer types.

The inttypes.h header file defines macros that expand to a literal character string that forms a conversion specifier suitable for use with formatted input functions.

The table below lists the macros that expand to conversion specifiers for input.

Table 1. Integer Conversion Specifiers for Input
Format	Type	Macro
decimal	`int8_t`	`SCNd8`
decimal	`int16_t`	`SCNd16`
decimal	`int32_t`	`SCNd32`
decimal	`int64_t`	`SCNd64`
decimal	`int_least8_t`	`SCNdLEAST8`
decimal	`int_least16_t`	`SCNdLEAST16`
decimal	`int_least32_t`	`SCNdLEAST32`
decimal	`int_least64_t`	`SCNdLEAST64`
decimal	`int_fast8_t`	`SCNdFAST8`
decimal	`int_fast16_t`	`SCNdFAST16`
decimal	`int_fast32_t`	`SCNdFAST32`
decimal	`int_fast64_t`	`SCNdFAST64`
decimal	`intmax_t`	`SCNdMAX`
decimal	`intptr_t`	`SCNdPTR`
octal, decimal, or hexadecimal	`int8_t`	`SCNi8`
octal, decimal, or hexadecimal	`int16_t`	`SCNi16`
octal, decimal, or hexadecimal	`int32_t`	`SCNi32`
octal, decimal, or hexadecimal	`int64_t`	`SCNi64`
octal, decimal, or hexadecimal	`int_least8_t`	`SCNiLEAST8`
octal, decimal, or hexadecimal	`int_least16_t`	`SCNiLEAST16`
octal, decimal, or hexadecimal	`int_least32_t`	`SCNiLEAST32`
octal, decimal, or hexadecimal	`int_least64_t`	`SCNiLEAST64`
octal, decimal, or hexadecimal	`int_fast8_t`	`SCNiFAST8`
octal, decimal, or hexadecimal	`int_fast16_t`	`SCNiFAST16`
octal, decimal, or hexadecimal	`int_fast32_t`	`SCNiFAST32`
octal, decimal, or hexadecimal	`int_fast64_t`	`SCNiFAST64`
octal, decimal, or hexadecimal	`intmax_t`	`SCNiMAX`
octal, decimal, or hexadecimal	`intptr_t`	`SCNiPTR`
unsigned octal	`int8_t`	`SCNo8`
unsigned octal	`int16_t`	`SCNo16`
unsigned octal	`int32_t`	`SCNo32`
unsigned octal	`int64_t`	`SCNo64`
unsigned octal	`int_least8_t`	`SCNoLEAST8`
unsigned octal	`int_least16_t`	`SCNoLEAST16`
unsigned octal	`int_least32_t`	`SCNoLEAST32`
unsigned octal	`int_least64_t`	`SCNoLEAST64`
unsigned octal	`int_fast8_t`	`SCNoFAST8`
unsigned octal	`int_fast16_t`	`SCNoFAST16`
unsigned octal	`int_fast32_t`	`SCNoFAST32`
unsigned octal	`int_fast64_t`	`SCNoFAST64`
unsigned octal	`intmax_t`	`SCNoMAX`
unsigned octal	`intptr_t`	`SCNoPTR`
unsigned decimal	`int8_t`	`SCNu8`
unsigned decimal	`int16_t`	`SCNu16`
unsigned decimal	`int32_t`	`SCNu32`
unsigned decimal	`int64_t`	`SCNu64`
unsigned decimal	`int_least8_t`	`SCNuLEAST8`
unsigned decimal	`int_least16_t`	`SCNuLEAST16`
unsigned decimal	`int_least32_t`	`SCNuLEAST32`
unsigned decimal	`int_least64_t`	`SCNuLEAST64`
unsigned decimal	`int_fast8_t`	`SCNuFAST8`
unsigned decimal	`int_fast16_t`	`SCNuFAST16`
unsigned decimal	`int_fast32_t`	`SCNuFAST32`
unsigned decimal	`int_fast64_t`	`SCNuFAST64`
unsigned decimal	`intmax_t`	`SCNuMAX`
unsigned decimal	`intptr_t`	`SCNuPTR`
unsigned hexadecimal	`int8_t`	`SCNx8`
unsigned hexadecimal	`int16_t`	`SCNx16`
unsigned hexadecimal	`int32_t`	`SCNx32`
unsigned hexadecimal	`int64_t`	`SCNx64`
unsigned hexadecimal	`int_least8_t`	`SCNxLEAST8`
unsigned hexadecimal	`int_least16_t`	`SCNxLEAST16`
unsigned hexadecimal	`int_least32_t`	`SCNxLEAST32`
unsigned hexadecimal	`int_least64_t`	`SCNxLEAST64`
unsigned hexadecimal	`int_fast8_t`	`SCNxFAST8`
unsigned hexadecimal	`int_fast16_t`	`SCNxFAST16`
unsigned hexadecimal	`int_fast32_t`	`SCNxFAST32`
unsigned hexadecimal	`int_fast64_t`	`SCNxFAST64`
unsigned hexadecimal	`intmax_t`	`SCNxMAX`
unsigned hexadecimal	`intptr_t`	`SCNxPTR`

Listing: Example of Integer Input


#include <stdio.h> 
#include <inttypes.h> 
int main(void) 
{ 
int8_t i8; 
intmax_t im; 
printf("Enter an integer surrounded by ! marks.\n"); 
scanf("!%" SCNd8 "!", &i8); 
printf("Enter a large integer\n"); 
printf("in hexadecimal, octal, or decimal.\n"); 
scanf("%" SCNiMAX, &im); 
return 0; 
} 
Output: 
Enter an 8-bit integer surrounded by ! marks. 
!63! 
Enter a large integer 
in hexadecimal, octal, or decimal. 
175812759