mirror of https://github.com/mkerrisk/man-pages
164 lines
6.1 KiB
Plaintext
164 lines
6.1 KiB
Plaintext
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "<inttypes.h>" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" <inttypes.h>
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.SH NAME
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inttypes.h \- fixed size integer types
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.SH SYNOPSIS
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.LP
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\fB#include <inttypes.h>\fP
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.SH DESCRIPTION
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.LP
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Some of the functionality described on this reference page extends
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the ISO\ C standard. Applications shall define
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the appropriate feature test macro (see the System Interfaces volume
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of IEEE\ Std\ 1003.1-2001, Section 2.2, The Compilation Environment)
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to enable the visibility of these symbols in this
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header.
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.LP
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The \fI<inttypes.h>\fP header shall include the \fI<stdint.h>\fP
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header.
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.LP
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The \fI<inttypes.h>\fP header shall include a definition of at least
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the following type:
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.TP 7
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\fBimaxdiv_t\fP
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Structure type that is the type of the value returned by the \fIimaxdiv\fP()
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function.
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.sp
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.LP
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The following macros shall be defined. Each expands to a character
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string literal containing a conversion specifier, possibly
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modified by a length modifier, suitable for use within the \fIformat\fP
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argument of a formatted input/output function when
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converting the corresponding integer type. These macros have the general
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form of PRI (character string literals for the \fIfprintf\fP() and
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\fIfwprintf\fP() family of
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functions) or SCN (character string literals for the \fIfscanf\fP()
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and \fIfwscanf\fP() family of functions), followed by the conversion
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specifier, followed by a name
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corresponding to a similar type name in \fI<stdint.h>\fP. In these
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names, \fIN\fP
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represents the width of the type as described in \fI<stdint.h>\fP.
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For example,
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\fIPRIdFAST32\fP can be used in a format string to print the value
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of an integer of type \fBint_fast32_t\fP.
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.LP
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The \fIfprintf\fP() macros for signed integers are:
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.TS C
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center; l2 l2 l2 l2 l.
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PRId\fIN\fP PRIdLEAST\fIN\fP PRIdFAST\fIN\fP PRIdMAX PRIdPTR
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PRIi\fIN\fP PRIiLEAST\fIN\fP PRIiFAST\fIN\fP PRIiMAX PRIiPTR
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.TE
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.LP
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The \fIfprintf\fP() macros for unsigned integers are:
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.TS C
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center; l2 l2 l2 l2 l.
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PRIo\fIN\fP PRIoLEAST\fIN\fP PRIoFAST\fIN\fP PRIoMAX PRIoPTR
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PRIu\fIN\fP PRIuLEAST\fIN\fP PRIuFAST\fIN\fP PRIuMAX PRIuPTR
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PRIx\fIN\fP PRIxLEAST\fIN\fP PRIxFAST\fIN\fP PRIxMAX PRIxPTR
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PRIX\fIN\fP PRIXLEAST\fIN\fP PRIXFAST\fIN\fP PRIXMAX PRIXPTR
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.TE
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.LP
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The \fIfscanf\fP() macros for signed integers are:
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.TS C
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center; l2 l2 l2 l2 l.
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SCNd\fIN\fP SCNdLEAST\fIN\fP SCNdFAST\fIN\fP SCNdMAX SCNdPTR
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SCNi\fIN\fP SCNiLEAST\fIN\fP SCNiFAST\fIN\fP SCNiMAX SCNiPTR
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.TE
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.LP
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The \fIfscanf\fP() macros for unsigned integers are:
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.TS C
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center; l2 l2 l2 l2 l.
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SCNo\fIN\fP SCNoLEAST\fIN\fP SCNoFAST\fIN\fP SCNoMAX SCNoPTR
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SCNu\fIN\fP SCNuLEAST\fIN\fP SCNuFAST\fIN\fP SCNuMAX SCNuPTR
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SCNx\fIN\fP SCNxLEAST\fIN\fP SCNxFAST\fIN\fP SCNxMAX SCNxPTR
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.TE
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.LP
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For each type that the implementation provides in \fI<stdint.h>\fP,
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the
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corresponding \fIfprintf\fP() and \fIfwprintf\fP() macros shall be
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defined and the corresponding \fIfscanf\fP() and \fIfwscanf\fP() macros
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shall be defined
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unless the implementation does not have a suitable modifier for the
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type.
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.LP
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The following shall be declared as functions and may also be defined
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as macros. Function prototypes shall be provided.
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.sp
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.RS
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.nf
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\fBintmax_t imaxabs(intmax_t);
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imaxdiv_t imaxdiv(intmax_t, intmax_t);
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intmax_t strtoimax(const char *restrict, char **restrict, int);
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uintmax_t strtoumax(const char *restrict, char **restrict, int);
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intmax_t wcstoimax(const wchar_t *restrict, wchar_t **restrict, int);
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uintmax_t wcstoumax(const wchar_t *restrict, wchar_t **restrict, int);
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\fP
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.fi
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.RE
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.SH EXAMPLES
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.sp
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.RS
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.nf
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\fB#include <inttypes.h>
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#include <wchar.h>
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int main(void)
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{
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uintmax_t i = UINTMAX_MAX; // This type always exists.
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wprintf(L"The largest integer value is %020"
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PRIxMAX "\\n", i);
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return 0;
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}
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\fP
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.fi
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.RE
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.LP
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\fIThe following sections are informative.\fP
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.SH APPLICATION USAGE
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.LP
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The purpose of \fI<inttypes.h>\fP is to provide a set of integer types
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whose definitions are consistent across machines
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and independent of operating systems and other implementation idiosyncrasies.
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It defines, via \fBtypedef\fP, integer types of
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various sizes. Implementations are free to \fBtypedef\fP them as ISO\ C
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standard integer types or extensions that they
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support. Consistent use of this header will greatly increase the portability
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of applications across platforms.
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.SH RATIONALE
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.LP
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The ISO/IEC\ 9899:1990 standard specified that the language should
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support four signed and unsigned integer data types-
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\fBchar\fP, \fBshort\fP, \fBint\fP, and \fBlong\fP- but placed very
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little requirement on their size other than that \fBint\fP
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and \fBshort\fP be at least 16 bits and \fBlong\fP be at least as
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long as \fBint\fP and not smaller than 32 bits. For 16-bit
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systems, most implementations assigned 8, 16, 16, and 32 bits to \fBchar\fP,
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\fBshort\fP, \fBint\fP, and \fBlong\fP,
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respectively. For 32-bit systems, the common practice has been to
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assign 8, 16, 32, and 32 bits to these types. This difference in
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\fBint\fP size can create some problems for users who migrate from
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one system to another which assigns different sizes to integer
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types, because the ISO\ C standard integer promotion rule can produce
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silent changes unexpectedly. The need for defining an
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extended integer type increased with the introduction of 64-bit systems.
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.SH FUTURE DIRECTIONS
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.LP
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Macro names beginning with PRI or SCN followed by any lowercase letter
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or \fB'X'\fP may be added to the macros defined in the
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\fI<inttypes.h>\fP header.
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.SH SEE ALSO
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.LP
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The System Interfaces volume of IEEE\ Std\ 1003.1-2001, \fIimaxdiv\fP()
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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