C Standard Library

C - <inttypes.h> (inttypes.h)



The C <inttypes.h> header provides library support for width-based integral types. Including this header automatically includes also <stdint.h> (which defines width-based integral types).

Library Macros

Macro constants

Format constants for the printf() family of functions

MacrosDescription
PRId8
PRId16
PRId32
PRId64
PRIdLEAST8
PRIdLEAST16
PRIdLEAST32
PRIdLEAST64
PRIdFAST8
PRIdFAST16
PRIdFAST32
PRIdFAST64
PRIdMAX
PRIdPTR

format conversion specifier to output a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to d for int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

PRIi8
PRIi16
PRIi32
PRIi64
PRIiLEAST8
PRIiLEAST16
PRIiLEAST32
PRIiLEAST64
PRIiFAST8
PRIiFAST16
PRIiFAST32
PRIiFAST64
PRIiMAX
PRIiPTR

format conversion specifier to output a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to i for int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

PRIu8
PRIu16
PRIu32
PRIu64
PRIuLEAST8
PRIuLEAST16
PRIuLEAST32
PRIuLEAST64
PRIuFAST8
PRIuFAST16
PRIuFAST32
PRIuFAST64
PRIuMAX
PRIuPTR

format conversion specifier to output an unsigned decimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to u for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

PRIo8
PRIo16
PRIo32
PRIo64
PRIoLEAST8
PRIoLEAST16
PRIoLEAST32
PRIoLEAST64
PRIoFAST8
PRIoFAST16
PRIoFAST32
PRIoFAST64
PRIoMAX
PRIoPTR

format conversion specifier to output an unsigned octal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to o for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

PRIx8
PRIx16
PRIx32
PRIx64
PRIxLEAST8
PRIxLEAST16
PRIxLEAST32
PRIxLEAST64
PRIxFAST8
PRIxFAST16
PRIxFAST32
PRIxFAST64
PRIxMAX
PRIxPTR

format conversion specifier to output an unsigned lowercase hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to x for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

PRIX8
PRIX16
PRIX32
PRIX64
PRIXLEAST8
PRIXLEAST16
PRIXLEAST32
PRIXLEAST64
PRIXFAST8
PRIXFAST16
PRIXFAST32
PRIXFAST64
PRIXMAX
PRIXPTR

format conversion specifier to output an unsigned uppercase hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to X for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.


Format constants for the scanf() family of functions

MacrosDescription
SCNd8
SCNd16
SCNd32
SCNd64
SCNdLEAST8
SCNdLEAST16
SCNdLEAST32
SCNdLEAST64
SCNdFAST8
SCNdFAST16
SCNdFAST32
SCNdFAST64
SCNdMAX
SCNdPTR

format conversion specifier to input a signed decimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to d for int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

SCNi8
SCNi16
SCNi32
SCNi64
SCNiLEAST8
SCNiLEAST16
SCNiLEAST32
SCNiLEAST64
SCNiFAST8
SCNiFAST16
SCNiFAST32
SCNiFAST64
SCNiMAX
SCNiPTR

format conversion specifier to input a signed decimal/octal/hexadecimal integer value of type int8_t, int16_t, int32_t, int64_t, int_least8_t, int_least16_t, int_least32_t, int_least64_t, int_fast8_t, int_fast16_t, int_fast32_t, int_fast64_t, intmax_t, intptr_t respectively, equivalent to i for int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

SCNu8
SCNu16
SCNu32
SCNu64
SCNuLEAST8
SCNuLEAST16
SCNuLEAST32
SCNuLEAST64
SCNuFAST8
SCNuFAST16
SCNuFAST32
SCNuFAST64
SCNuMAX
SCNuPTR

format conversion specifier to input an unsigned decimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to u for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

SCNo8
SCNo16
SCNo32
SCNo64
SCNoLEAST8
SCNoLEAST16
SCNoLEAST32
SCNoLEAST64
SCNoFAST8
SCNoFAST16
SCNoFAST32
SCNoFAST64
SCNoMAX
SCNoPTR

format conversion specifier to input an unsigned octal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to o for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.

SCNx8
SCNx16
SCNx32
SCNx64
SCNxLEAST8
SCNxLEAST16
SCNxLEAST32
SCNxLEAST64
SCNxFAST8
SCNxFAST16
SCNxFAST32
SCNxFAST64
SCNxMAX
SCNxPTR

format conversion specifier to input an unsigned hexadecimal integer value of type uint8_t, uint16_t, uint32_t, uint64_t, uint_least8_t, uint_least16_t, uint_least32_t, uint_least64_t, uint_fast8_t, uint_fast16_t, uint_fast32_t, uint_fast64_t, uintmax_t, uintptr_t respectively, equivalent to x for unsigned int.

These width-based integral types are defined in <stdint.h> header which is included in this header.


Example:

The example below describes how to use these macro constants with printf() and scanf() functions.

#include <stdio.h>
#include <inttypes.h>

int main (){
  int64_t x, y;

  printf("Please, enter a number: ");
  scanf("%" SCNd64, &x);

  printf("Please, enter another number: ");
  scanf("%" SCNd64, &y);

  printf("%" PRId64 " by %" PRId64 " gives %" PRId64, x, y, x*y);

  return 0;
}

The possible output of the above code will be:

Please, enter a number: 10
Please, enter another number: 15
10 by 15 gives 150

Example:

Lets assume that we have a file called test.txt in the current working directory. In the example below, these macro constants is used with fprintf() function to write the formatted string in this file.

#include <stdio.h>
#include <inttypes.h>

int main (){
  //open the file in write mode
  FILE *pFile = fopen("test.txt", "w+");

  fprintf(pFile, "Decimals: %" PRId16 " %" PRId16 " \n", 200, 300);
  fprintf(pFile, "More Decimals: %" PRId64 " %" PRId64 " \n", 20000L, 30000L);
  fprintf(pFile, "Octals: %" PRIo16 " %#" PRIo16 " \n", 100, 100);
  fprintf(pFile, "Hexadecimals: %" PRIx16 " %#" PRIx16 " %" PRIX16 
                 " %#" PRIX16 " \n", 100, 100, 100, 100);
  fprintf(pFile, "Padded number = %05" PRId16 " \n", 89);
  fprintf(pFile, "Number with Width = %*" PRId16 " \n", 5, 89);

  //set the position to the start
  rewind(pFile);

  //display the content of the file
  int c = getc(pFile);
  while(c != EOF) {
    putchar(c);
    c = getc(pFile);
  }

  //close the file
  fclose (pFile);

  return 0;
}

The output of the above code will be:

Decimals: 200 300 
More Decimals: 20000 30000 
Octals: 144 0144 
Hexadecimals: 64 0x64 64 0X64 
Padded number = 00089 
Number with Width =    89 

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