inttypes.h(0p) — Linux manual page


inttypes.h(0P)          POSIX Programmer's Manual         inttypes.h(0P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       inttypes.h — fixed size integer types

SYNOPSIS         top

       #include <inttypes.h>

DESCRIPTION         top

       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 POSIX.1‐2017, 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 define at least the following

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

       wchar_t     As described in <stddef.h>.

       The <inttypes.h> header shall define the following macros. 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

       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);

       The following sections are informative.

EXAMPLES         top

       #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 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, through 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         top

       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.


       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         top


       The System Interfaces volume of POSIX.1‐2017, Section 2.2, The
       Compilation Environment, imaxabs(3p), imaxdiv(3p), strtoimax(3p),

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see .

IEEE/The Open Group               2017                    inttypes.h(0P)

Pages that refer to this page: arpa_inet.h(0p)netdb.h(0p)netinet_in.h(0p)stdint.h(0p)fprintf(3p)fscanf(3p)fwprintf(3p)fwscanf(3p)htonl(3p)imaxabs(3p)imaxdiv(3p)strtoimax(3p)wcstoimax(3p)