<stdio.h>

The <stdio.h> include file defines constants, macros, and types, and declares stream input and output functions. The stream I/O functions are:


`_C_Get_Ssn_Handle` `clearerr` `fclose` `fdopen`² `feof` `ferror` `fflush` `fgetc` `fgetpos` `fgets` `fgetwc¹` `fgetws¹` `fileno`² `fopen`	`fprintf` `fputc` `_fputchar` `fputs` `fputwc¹` `fputws¹` `fread` `freopen` `fscanf` `fseek` `fsetpos` `ftell` `fwide¹` `fwprintf¹`	`fwrite` `fwscanf¹` `getc` `getchar` `gets` `getwc¹` `getwchar¹` `perror` `printf` `putc` `putchar` `puts` `putwc¹` `putwchar¹`	`remove` `rename` `rewind` `scanf` `setbuf` `setvbuf` `snprintf` `sprintf` `sscanf` `tmpfile` `tmpnam` `ungetc` `ungetwc¹` `vfprintf`	`vfscanf` `vfwprintf¹` `vfwscanf`¹ `vprintf` `vscanf` `vsscanf` `vsnprintf` `vsprintf` `vwprintf¹` `vwscanf`¹ `wfopen`² `wprintf¹` `wscanf¹`
Note: ¹ These functions are not available when either LOCALETYPE(CLD) or SYSIFCOPT(NOIFSIO) is specified on the compilation command. Note: ² These functions are available when SYSIFCOPT(*IFSIO) is specified on the compilation command.

The <stdio.h> include file also defines the macros that are listed below. You can use these constants in your programs, but you should not alter their values.

BUFSIZ: Specifies the buffer size that the setbuf library function will use when you are allocating buffers for stream I/O. This value establishes the size of system-allocated buffers and is used with setbuf.
EOF: The value that is returned by an I/O function when the end of the file (or in some cases, an error) is found.
FOPEN_MAX: The number of files that can be opened simultaneously.
FILENAME_MAX: The longest file name that is supported. If there is no reasonable limit, FILENAME_MAX will be the recommended size.
L_tmpnam: The size of the longest temporary name that can be generated by the tmpnam function.
TMP_MAX: The minimum number of unique file names that can be generated by the tmpnam function.
NULL: A pointer guaranteed not to point to a data object.

The FILE structure type is defined in <stdio.h>. Stream I⁄O functions use a pointer to the FILE type to get access to a given stream. The system uses the information in the FILE structure to maintain the stream.

When integrated file system is enabled with a compilation parameter SYSIFCOPT(*IFSIO), ifs.h is included into <stdio.h>.

The C standard streams stdin, stdout, and stderr are also defined in <stdio.h>.

The macros SEEK_CUR, SEEK_END, and SEEK_SET expand to integral constant expressions and can be used as the third argument to fseek().

The macros _IOFBF, _IOLBF, and _IONBF expand to integral constant expressions with distinct values suitable for use as the third argument to the setvbuf function.

The type fpos_t is defined in <stdio.h> for use with fgetpos() and fsetpos().

See <stddef.h> for more information about NULL.