NAME

       inttypes.h - fixed size integer types

SYNOPSIS

       #include <inttypes.h>

DESCRIPTION

       Some  of  the  functionality  described on this reference page extends the ISO C standard.
       Applications shall define the appropriate feature test macro (see  the  System  Interfaces
       volume  of  IEEE Std 1003.1-2001,  Section 2.2, The Compilation Environment) to enable the
       visibility of these symbols in this header.

       The <inttypes.h> header shall include the <stdint.h> header.

       The <inttypes.h> header shall include a definition of at least the following type:

       imaxdiv_t
              Structure type that is the type of the value returned by the imaxdiv() function.

       The following macros shall  be  defined.  Each  expands  to  a  character  string  literal
       containing  a  conversion  specifier, possibly modified by a length modifier, suitable for
       use within the format argument of a formatted input/output function  when  converting  the
       corresponding  integer  type.  These macros have the general form of PRI (character string
       literals for the fprintf() and fwprintf() family of functions) or  SCN  (character  string
       literals  for  the fscanf() and fwscanf() family of functions), followed by the conversion
       specifier, followed by a name corresponding to a similar type name in <stdint.h>. In these
       names,  N  represents  the  width  of  the  type as described in <stdint.h>.  For example,
       PRIdFAST32 can be used in a format string to  print  the  value  of  an  integer  of  type
       int_fast32_t.

       The fprintf() macros for signed integers are:

                             PRIdN  PRIdLEASTN  PRIdFASTN  PRIdMAX  PRIdPTR
                             PRIiN  PRIiLEASTN  PRIiFASTN  PRIiMAX  PRIiPTR

       The fprintf() macros for unsigned integers are:

                             PRIoN  PRIoLEASTN  PRIoFASTN  PRIoMAX  PRIoPTR
                             PRIuN  PRIuLEASTN  PRIuFASTN  PRIuMAX  PRIuPTR
                             PRIxN  PRIxLEASTN  PRIxFASTN  PRIxMAX  PRIxPTR
                             PRIXN  PRIXLEASTN  PRIXFASTN  PRIXMAX  PRIXPTR

       The fscanf() macros for signed integers are:

                             SCNdN  SCNdLEASTN  SCNdFASTN  SCNdMAX  SCNdPTR
                             SCNiN  SCNiLEASTN  SCNiFASTN  SCNiMAX  SCNiPTR

       The fscanf() macros for unsigned integers are:

                             SCNoN  SCNoLEASTN  SCNoFASTN  SCNoMAX  SCNoPTR
                             SCNuN  SCNuLEASTN  SCNuFASTN  SCNuMAX  SCNuPTR
                             SCNxN  SCNxLEASTN  SCNxFASTN  SCNxMAX  SCNxPTR

       For  each type that the implementation provides in <stdint.h>, the corresponding fprintf()
       and fwprintf() macros shall be defined and the corresponding fscanf() and fwscanf() macros
       shall be defined unless the implementation does not have a suitable modifier for the type.

       The  following  shall be declared as functions and may also be defined as macros. Function
       prototypes shall be provided.

              intmax_t  imaxabs(intmax_t);
              imaxdiv_t imaxdiv(intmax_t, intmax_t);
              intmax_t  strtoimax(const char *restrict, char **restrict, int);
              uintmax_t strtoumax(const char *restrict, char **restrict, int);
              intmax_t  wcstoimax(const wchar_t *restrict, wchar_t **restrict, int);
              uintmax_t wcstoumax(const wchar_t *restrict, wchar_t **restrict, int);

EXAMPLES

              #include <inttypes.h>
              #include <wchar.h>
              int main(void)
              {
                  uintmax_t i = UINTMAX_MAX; // This type always exists.
                  wprintf(L"The largest integer value is %020"
                      PRIxMAX "\n", i);
                  return 0;
              }

       The following sections are informative.

APPLICATION USAGE

       The purpose of <inttypes.h> is to provide a set of integer  types  whose  definitions  are
       consistent  across  machines and independent of operating systems and other implementation
       idiosyncrasies.  It defines, via typedef, integer types of various sizes.  Implementations
       are  free to typedef them as ISO C standard integer types or extensions that they support.
       Consistent use of this header will greatly increase the portability of applications across
       platforms.

RATIONALE

       The  ISO/IEC 9899:1990 standard specified that the language should support four signed and
       unsigned integer  data  types-  char,  short,  int,  and  long-  but  placed  very  little
       requirement on their size other than that int and short be at least 16 bits and long be at
       least  as  long  as  int  and  not  smaller  than  32  bits.  For  16-bit  systems,   most
       implementations  assigned  8,  16,  16,  and  32  bits  to  char,  short,  int,  and long,
       respectively. For 32-bit systems, the common practice has been to assign 8, 16, 32, and 32
       bits  to  these  types. This difference in int size can create some problems for users who
       migrate from one system to another which assigns different sizes to integer types, because
       the  ISO C  standard  integer  promotion rule can produce silent changes unexpectedly. The
       need for defining an extended integer type  increased  with  the  introduction  of  64-bit
       systems.

FUTURE DIRECTIONS

       Macro names beginning with PRI or SCN followed by any lowercase letter or 'X' may be added
       to the macros defined in the <inttypes.h> header.

SEE ALSO

       The System Interfaces volume of IEEE Std 1003.1-2001, imaxdiv()

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1,  2003  Edition,  Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard,  the  original  IEEE  and  The  Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .