[c.files]

# 31 Input/output library [[input.output]](./#input.output)

## 31.13 C library files [c.files]

### [31.13.1](#cstdio.syn) Header <cstdio> synopsis [[cstdio.syn]](cstdio.syn)

[ð](#header:%3ccstdio%3e)

#define __STDC_VERSION_STDIO_H__ 202311Lnamespace std {using size_t = *see [[support.types.layout]](support.types.layout "17.2.4 Sizes, alignments, and offsets")*; using FILE = *see below*; using fpos_t = *see below*;}#define NULL *see [[support.types.nullptr]](support.types.nullptr "17.2.3 Null pointers")*#define _IOFBF *see below*#define _IOLBF *see below*#define _IONBF *see below*#define BUFSIZ *see below*#define EOF *see below*#define FOPEN_MAX *see below*#define FILENAME_MAX *see below*#define _PRINTF_NAN_LEN_MAX *see below*#define L_tmpnam *see below*#define SEEK_CUR *see below*#define SEEK_END *see below*#define SEEK_SET *see below*#define TMP_MAX *see below*#define stderr *see below*#define stdin *see below*#define stdout *see below*namespace std {int remove(const char* filename); int rename(const char* old_p, const char* new_p);
 FILE* tmpfile(); char* tmpnam(char* s); int fclose(FILE* stream); int fflush(FILE* stream);
 FILE* fopen(const char* filename, const char* mode);
 FILE* freopen(const char* filename, const char* mode, FILE* stream); void setbuf(FILE* stream, char* buf); int setvbuf(FILE* stream, char* buf, int mode, size_t size); int fprintf(FILE* stream, const char* format, ...); int fscanf(FILE* stream, const char* format, ...); int printf(const char* format, ...); int scanf(const char* format, ...); int snprintf(char* s, size_t n, const char* format, ...); int sprintf(char* s, const char* format, ...); int sscanf(const char* s, const char* format, ...); int vfprintf(FILE* stream, const char* format, va_list arg); int vfscanf(FILE* stream, const char* format, va_list arg); int vprintf(const char* format, va_list arg); int vscanf(const char* format, va_list arg); int vsnprintf(char* s, size_t n, const char* format, va_list arg); int vsprintf(char* s, const char* format, va_list arg); int vsscanf(const char* s, const char* format, va_list arg); int fgetc(FILE* stream); char* fgets(char* s, int n, FILE* stream); int fputc(int c, FILE* stream); int fputs(const char* s, FILE* stream); int getc(FILE* stream); int getchar(); int putc(int c, FILE* stream); int putchar(int c); int puts(const char* s); int ungetc(int c, FILE* stream);
 size_t fread(void* ptr, size_t size, size_t nmemb, FILE* stream);
 size_t fwrite(const void* ptr, size_t size, size_t nmemb, FILE* stream); int fgetpos(FILE* stream, fpos_t* pos); int fseek(FILE* stream, long int offset, int whence); int fsetpos(FILE* stream, const fpos_t* pos); long int ftell(FILE* stream); void rewind(FILE* stream); void clearerr(FILE* stream); int feof(FILE* stream); int ferror(FILE* stream); void perror(const char* s);}

[1](#cstdio.syn-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L18970)

The contents and meaning of the header [<cstdio>](#header:%3ccstdio%3e "31.13.1 Header <cstdio> synopsis [cstdio.syn]") are the same as the C standard library header [<stdio.h>](support.c.headers.general#header:%3cstdio.h%3e "17.15.1 General [support.c.headers.general]")[.](#cstdio.syn-1.sentence-1)

[2](#cstdio.syn-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L18974)

The return from each function call
that delivers data
to the host environment
to be written to a file (See also: ISO/IEC 9899:2024, 7.21.3)
is an observable checkpoint ([[intro.abstract]](intro.abstract "4.1.2 Abstract machine"))[.](#cstdio.syn-2.sentence-1)

[3](#cstdio.syn-3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L18981)

Calls to the function tmpnam with an argument that is a null pointer value may
introduce a data race ([[res.on.data.races]](res.on.data.races "16.4.6.10 Data race avoidance")) with other calls to tmpnam with
an argument that is a null pointer value[.](#cstdio.syn-3.sentence-1)

See also: ISO/IEC 9899:2024, 7.23

### [31.13.2](#cinttypes.syn) Header <cinttypes> synopsis [[cinttypes.syn]](cinttypes.syn)

[ð](#header:%3ccinttypes%3e)

#include <cstdint> // see [[cstdint.syn]](cstdint.syn "17.4.1 Header <cstdint> synopsis")namespace std {using imaxdiv_t = *see below*; constexpr intmax_t imaxabs(intmax_t j); constexpr imaxdiv_t imaxdiv(intmax_t numer, intmax_t denom);
 intmax_t strtoimax(const char* nptr, char** endptr, int base);
 uintmax_t strtoumax(const char* nptr, char** endptr, int base);
 intmax_t wcstoimax(const wchar_t* nptr, wchar_t** endptr, int base);
 uintmax_t wcstoumax(const wchar_t* nptr, wchar_t** endptr, int base); constexpr intmax_t abs(intmax_t); // optional, see belowconstexpr imaxdiv_t div(intmax_t, intmax_t); // optional, see below}#define __STDC_VERSION_INTTYPES_H__ 202311L#define PRId*N* *see below*#define PRIi*N* *see below*#define PRIo*N* *see below*#define PRIu*N* *see below*#define PRIx*N* *see below*#define PRIX*N* *see below*#define PRIb*N* *see below*#define PRIB*N* *see below*#define SCNd*N* *see below*#define SCNi*N* *see below*#define SCNo*N* *see below*#define SCNu*N* *see below*#define SCNx*N* *see below*#define SCNb*N* *see below*#define PRIdLEAST*N* *see below*#define PRIiLEAST*N* *see below*#define PRIoLEAST*N* *see below*#define PRIuLEAST*N* *see below*#define PRIxLEAST*N* *see below*#define PRIXLEAST*N* *see below*#define PRIbLEAST*N* *see below*#define PRIBLEAST*N* *see below*#define SCNdLEAST*N* *see below*#define SCNiLEAST*N* *see below*#define SCNoLEAST*N* *see below*#define SCNuLEAST*N* *see below*#define SCNxLEAST*N* *see below*#define SCNbLEAST*N* *see below*#define PRIdFAST*N* *see below*#define PRIiFAST*N* *see below*#define PRIoFAST*N* *see below*#define PRIuFAST*N* *see below*#define PRIxFAST*N* *see below*#define PRIXFAST*N* *see below*#define PRIbFAST*N* *see below*#define PRIBFAST*N* *see below*#define SCNdFAST*N* *see below*#define SCNiFAST*N* *see below*#define SCNoFAST*N* *see below*#define SCNuFAST*N* *see below*#define SCNxFAST*N* *see below*#define SCNbFAST*N* *see below*#define PRIdMAX *see below*#define PRIiMAX *see below*#define PRIoMAX *see below*#define PRIuMAX *see below*#define PRIxMAX *see below*#define PRIXMAX *see below*#define PRIbMAX *see below*#define PRIBMAX *see below*#define SCNdMAX *see below*#define SCNiMAX *see below*#define SCNoMAX *see below*#define SCNuMAX *see below*#define SCNxMAX *see below*#define SCNbMAX *see below*#define PRIdPTR *see below*#define PRIiPTR *see below*#define PRIoPTR *see below*#define PRIuPTR *see below*#define PRIxPTR *see below*#define PRIXPTR *see below*#define PRIbPTR *see below*#define PRIBPTR *see below*#define SCNdPTR *see below*#define SCNiPTR *see below*#define SCNoPTR *see below*#define SCNuPTR *see below*#define SCNxPTR *see below*#define SCNbPTR *see below*

[1](#cinttypes.syn-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L19133)

The contents and meaning of the header [<cinttypes>](#header:%3ccinttypes%3e "31.13.2 Header <cinttypes> synopsis [cinttypes.syn]") are the same as the C standard library header [<inttypes.h>](support.c.headers.general#header:%3cinttypes.h%3e "17.15.1 General [support.c.headers.general]"),
with the following changes:

- [(1.1)](#cinttypes.syn-1.1)

The header [<cinttypes>](#header:%3ccinttypes%3e "31.13.2 Header <cinttypes> synopsis [cinttypes.syn]") includes the header [<cstdint>](cstdint.syn#header:%3ccstdint%3e "17.4.1 Header <cstdint> synopsis [cstdint.syn]") instead
of [<stdint.h>](support.c.headers.general#header:%3cstdint.h%3e "17.15.1 General [support.c.headers.general]"), and

- [(1.2)](#cinttypes.syn-1.2)

if and only if the type intmax_t designates an extended integer
type ([[basic.fundamental]](basic.fundamental "6.9.2 Fundamental types")), the following function signatures are added:constexpr intmax_t abs(intmax_t);constexpr imaxdiv_t div(intmax_t, intmax_t); which shall have the same semantics as the function signaturesconstexpr intmax_t imaxabs(intmax_t) andconstexpr imaxdiv_t imaxdiv(intmax_t, intmax_t), respectively[.](#cinttypes.syn-1.sentence-1)

See also: ISO/IEC 9899:2024, 7.8

[2](#cinttypes.syn-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L19155)

Each of the PRI macros listed in this subclause
is defined if and only if the implementation
defines the corresponding [*typedef-name*](dcl.typedef#nt:typedef-name "9.2.4 The typedef specifier [dcl.typedef]") in [[cstdint.syn]](cstdint.syn "17.4.1 Header <cstdint> synopsis")[.](#cinttypes.syn-2.sentence-1)

Each of the SCN macros listed in this subclause
is defined if and only if the implementation
defines the corresponding [*typedef-name*](dcl.typedef#nt:typedef-name "9.2.4 The typedef specifier [dcl.typedef]") in [[cstdint.syn]](cstdint.syn "17.4.1 Header <cstdint> synopsis") and
has a suitable fscanf length modifier for the type[.](#cinttypes.syn-2.sentence-2)

Each of the PRIB macros listed in this subclause
is defined if and only if fprintf supports
the B conversion specifier[.](#cinttypes.syn-2.sentence-3)
