trusty (7) inttypes.h.7posix.gz

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 .