0p:inttypes.h
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inttypes.h - fixed size integer types
#include <inttypes.h>
Contents |
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 speci-
fier, 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 liter-
als 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:
center; l2 l2 l2 l2 l. PRIdN PRIdLEASTN PRIdFASTN PRIdMAX PRIdPTR PRIiN PRIiLEASTN PRI-
iFASTN PRIiMAX PRIiPTR
The fprintf() macros for unsigned integers are:
center; l2 l2 l2 l2 l. PRIoN PRIoLEASTN PRIoFASTN PRIoMAX PRIoPTR PRIuN PRIuLEASTN PRIu-
FASTN PRIuMAX PRIuPTR PRIxN PRIxLEASTN PRIxFASTN PRIxMAX PRIxPTR PRIXN PRIXLEASTN PRIX-
FASTN PRIXMAX PRIXPTR
The fscanf() macros for signed integers are:
center; l2 l2 l2 l2 l. SCNdN SCNdLEASTN SCNdFASTN SCNdMAX SCNdPTR SCNiN SCNiLEASTN SCNi-
FASTN SCNiMAX SCNiPTR
The fscanf() macros for unsigned integers are:
center; l2 l2 l2 l2 l. SCNoN SCNoLEASTN SCNoFASTN SCNoMAX SCNoPTR SCNuN SCNuLEASTN SCNu-
FASTN 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 pro-
vided.
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.
RELATED
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, Stan-
dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
tions 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 .
IEEE/The Open Group 2003 <inttypes.h>(P)