5 Input and Output (stdio.h) ¶

This chapter comprises functions to manage files or other input/output streams. Among these functions are subroutines to generate or scan strings according to specifications from a format string.

The underlying facilities for input and output depend on the host system, but these functions provide a uniform interface.

The corresponding declarations are in stdio.h.

The reentrant versions of these functions use macros

_stdin_r(reent)
_stdout_r(reent)
_stderr_r(reent)

instead of the globals stdin, stdout, and stderr. The argument reent is a pointer to a reentrancy structure.

• clearerr, clearerr_unlocked—clear file or stream error indicator
• diprintf, vdiprintf—print to a file descriptor (integer only)
• dprintf, vdprintf—print to a file descriptor
• fclose—close a file
• fcloseall—close all files
• fdopen—turn open file into a stream
• feof, feof_unlocked—test for end of file
• ferror, ferror_unlocked—test whether read/write error has occurred
• fflush, fflush_unlocked—flush buffered file output
• fgetc, fgetc_unlocked—get a character from a file or stream
• fgetpos—record position in a stream or file
• fgets, fgets_unlocked—get character string from a file or stream
• fgetwc, getwc, fgetwc_unlocked, getwc_unlocked—get a wide character from a file or stream
• fgetws, fgetws_unlocked—get wide character string from a file or stream
• fileno, fileno_unlocked—return file descriptor associated with stream
• fmemopen—open a stream around a fixed-length string
• fopen—open a file
• fopencookie—open a stream with custom callbacks
• fpurge—discard pending file I/O
• fputc, fputc_unlocked—write a character on a stream or file
• fputs, fputs_unlocked—write a character string in a file or stream
• fputwc, putwc, fputwc_unlocked, putwc_unlocked—write a wide character on a stream or file
• fputws, fputws_unlocked—write a wide character string in a file or stream
• fread, fread_unlocked—read array elements from a file
• freopen—open a file using an existing file descriptor
• fseek, fseeko—set file position
• __fsetlocking—set or query locking mode on FILE stream
• fsetpos—restore position of a stream or file
• ftell, ftello—return position in a stream or file
• funopen, fropen, fwopen—open a stream with custom callbacks
• fwide—set and determine the orientation of a FILE stream
• fwrite, fwrite_unlocked—write array elements
• getc—read a character (macro)
• getc_unlocked—non-thread-safe version of getc (macro)
• getchar—read a character (macro)
• getchar_unlocked—non-thread-safe version of getchar (macro)
• getdelim—read a line up to a specified line delimiter
• getline—read a line from a file
• gets—get character string (obsolete, use fgets instead)
• getw—read a word (int)
• getwchar, getwchar_unlocked—read a wide character from standard input
• mktemp, mkstemp, mkostemp, mkstemps,
• open_memstream, open_wmemstream—open a write stream around an arbitrary-length string
• perror—print an error message on standard error
• putc—write a character (macro)
• putc_unlocked—non-thread-safe version of putc (macro)
• putchar—write a character (macro)
• putchar_unlocked—non-thread-safe version of putchar (macro)
• puts—write a character string
• putw—write a word (int)
• putwchar, putwchar_unlocked—write a wide character to standard output
• remove—delete a file’s name
• rename—rename a file
• rewind—reinitialize a file or stream
• setbuf—specify full buffering for a file or stream
• setbuffer—specify full buffering for a file or stream with size
• setlinebuf—specify line buffering for a file or stream
• setvbuf—specify file or stream buffering
• siprintf, fiprintf, iprintf, sniprintf, asiprintf, asniprintf—format output (integer only)
• siscanf, fiscanf, iscanf—scan and format non-floating input
• sprintf, fprintf, printf, snprintf, asprintf, asnprintf—format output
• sscanf, fscanf, scanf—scan and format input
• stdio_ext,__fbufsize,__fpending,__flbf,__freadable,__fwritable,__freading,__fwriting—access internals of FILE structure
• swprintf, fwprintf, wprintf—wide character format output
• swscanf, fwscanf, wscanf—scan and format wide character input
• tmpfile—create a temporary file
• tmpnam, tempnam—name for a temporary file
• ungetc—push data back into a stream
• ungetwc—push wide character data back into a stream
• vfprintf, vprintf, vsprintf, vsnprintf, vasprintf, vasnprintf—format argument list
• vfscanf, vscanf, vsscanf—format argument list
• vfwprintf, vwprintf, vswprintf—wide character format argument list
• vfwscanf, vwscanf, vswscanf—scan and format argument list from wide character input
• viprintf, vfiprintf, vsiprintf, vsniprintf, vasiprintf, vasniprintf—format argument list (integer only)
• viscanf, vfiscanf, vsiscanf—format argument list