Input/output

Names specified for `<stdio.h>`, “Input/output”
Name	Description	Notes				Source	Availability
`_IOFBF`	Full-buffering flag			M		`<stdio.h>`	C89	C90	C95	C99	C11
`_IOLBF`	Line-buffering flag			M		`<stdio.h>`	C89	C90	C95	C99	C11
`_IONBF`	No-buffering flag			M		`<stdio.h>`	C89	C90	C95	C99	C11
`BUFSIZ`	Built-in buffer size for I/O			M		`<stdio.h>`	C89	C90	C95	C99	C11
`clearerr()`	Clear error flag on stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`EOF`	End-of-stream indicator			M		Headers	C89	C90	C95	C99	C11
`errno_t`	Error-number type		?		T	Headers					C11
`FILE *`	Open stream				T	`<stdio.h>`	C89	C90	C95	C99	C11
`FILENAME_MAX`	Maximum filename length			M		`<stdio.h>`	C89	C90	C95	C99	C11
`FOPEN_MAX`	Maximum number of open files			M		`<stdio.h>`	C89	C90	C95	C99	C11
`fclose()`	Close stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`feof()`	Test for end of stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`ferror()`	Test for stream error				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fflush()`	Flush stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fgetc()`	Input character				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fgetpos()`	Get stream position				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fgets()`	Input line of characters				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fopen()`	Open file as stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fopen_s()`	Open file as stream				(·)	`<stdio.h>`					C11
`fpos_t`	Stream-position type				T	`<stdio.h>`	C89	C90	C95	C99	C11
`fprintf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`fputc()`	Output character				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fputs()`	Output line of characters				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fread()`	Input bytes				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`freopen()`	Re-open stream				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`freopen_s()`	Re-open stream				(·)	`<stdio.h>`					C11
`fscanf()`	Input formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fscanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11
`fseek()`	Set stream position				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fsetpos()`	Set stream position				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`ftell()`	Get stream position				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`fwrite()`	Output bytes				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`getc()`	Input character				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`getchar()`	Input character from standard input				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`gets()`	Input line of characters from standard input				(·)	`<stdio.h>`	C89	C90	C95	C99
`gets_s()`	Input line of characters from standard input		?		(·)	`<stdio.h>`					C11
`L_tmpnam`	Maximum temporary-file name length			M		`<stdio.h>`	C89	C90	C95	C99	C11
`L_tmpnam_s`	Maximum temporary-file name length		?	M		`<stdio.h>`					C11
`NULL`	Null pointer constant	L		M		Headers	C89	C90	C95	C99	C11
`perror()`	Report last error				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`printf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`printf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`putc()`	Output character				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`putchar()`	Output character to standard output				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`puts()`	Output line of characters to standard output				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`remove()`	Remove file				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`rename()`	Rename file				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`rewind()`	Reset stream position				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`rsize_t`	Implementation-defined size type with implied run-time constraints	L	?		T	Headers					C11
`SEEK_CUR`	File-position origin: current position			M		`<stdio.h>`	C89	C90	C95	C99	C11
`SEEK_END`	File-position origin: end			M		`<stdio.h>`	C89	C90	C95	C99	C11
`SEEK_SET`	File-position origin: beginning			M		`<stdio.h>`	C89	C90	C95	C99	C11
`scanf()`	Input formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`scanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11
`setbuf()`	Set stream buffer				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`setvbuf()`	Set stream buffer				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`size_t`	Implementation-defined size type	H			T	Headers	C89	C90	C95	C99	C11
`snprintf()`	Print formatted text				(·)	`<stdio.h>`				C99	C11
`snprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`sprintf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`sprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`sscanf()`	Input formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`sscanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11
`stderr`	Output stream for errors					`<stdio.h>`	C89	C90	C95	C99	C11
`stdin`	Standard input stream					`<stdio.h>`	C89	C90	C95	C99	C11
`stdout`	Standard output stream					`<stdio.h>`	C89	C90	C95	C99	C11
`TMP_MAX`	Maximum number of temporary files			M		`<stdio.h>`	C89	C90	C95	C99	C11
`TMP_MAX_S`	Maximum number of temporary files		?	M		`<stdio.h>`					C11
`tmpfile()`	Create temporary file				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`tmpfile_s()`	Create temporary file		?		(·)	`<stdio.h>`					C11
`tmpnam()`	Create temporary file name				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`tmpnam_s()`	Create temporary file name		?		(·)	`<stdio.h>`					C11
`ungetc()`	Replace character				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`vfprintf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`vfprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`vfscanf()`	Input formatted text				(·)	`<stdio.h>`				C99	C11
`vfscanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11
`vprintf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`vprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`vscanf()`	Input formatted text				(·)	`<stdio.h>`				C99	C11
`vscanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11
`vsnprintf()`	Print formatted text				(·)	`<stdio.h>`				C99	C11
`vsnprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`vsprintf()`	Print formatted text				(·)	`<stdio.h>`	C89	C90	C95	C99	C11
`vsprintf_s()`	Print formatted text		?		(·)	`<stdio.h>`					C11
`vsscanf()`	Input formatted text				(·)	`<stdio.h>`				C99	C11
`vsscanf_s()`	Input formatted text		?		(·)	`<stdio.h>`					C11

This header is available in C89, C90, C95, C99 and C11.

The header <stdio.h> provides several functions for input and output of bytes and characters with the environment; these are mainly byte-oriented. Wide-oriented equivalents are mostly in <wchar.h>. Some analogous functions work on internal arrays of char.