Manual Reference Pages  - <stdio.h> (P)


This manual page is part of the POSIX Programmer’s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.


Application Usage
Future Directions
See Also


stdio.h - standard buffered input/output


#include <stdio.h>


Some of the functionality described on this reference page extends the ISO C standard. Applications shall define the appropriate feature test macro (see the System Interfaces volume of IEEE Std 1003.1-2001, Section 2.2, The Compilation Environment) to enable the visibility of these symbols in this header.

The <stdio.h> header shall define the following macros as positive integer constant expressions:
BUFSIZ Size of <stdio.h> buffers.
_IOFBF Input/output fully buffered.
_IOLBF Input/output line buffered.
_IONBF Input/output unbuffered.
  Maximum size of character array to hold ctermid() output.
  Maximum size of character array to hold tmpnam() output.
  Seek relative to current position.
  Seek relative to end-of-file.
  Seek relative to start-of-file.

The following macros shall be defined as positive integer constant expressions which denote implementation limits:
  Maximum size in bytes of the longest filename string that the implementation guarantees can be opened.
  Number of streams which the implementation guarantees can be open simultaneously. The value is at least eight.
  Minimum number of unique filenames generated by tmpnam(). Maximum number of times an application can call tmpnam() reliably. The value of {TMP_MAX} is at least 25. On XSI-conformant systems, the value of {TMP_MAX} is at least 10000.

The following macro name shall be defined as a negative integer constant expression:
EOF End-of-file return value.

The following macro name shall be defined as a null pointer constant:
NULL Null pointer.

The following macro name shall be defined as a string constant:
  Default directory prefix for tempnam().

The following shall be defined as expressions of type "pointer to FILE" that point to the FILE objects associated, respectively, with the standard error, input, and output streams:
stderr Standard error output stream.
stdin Standard input stream.
stdout Standard output stream.

The following data types shall be defined through typedef:
FILE A structure containing information about a file.
fpos_t A non-array type containing all information needed to specify uniquely every position within a file.
va_list As described in <stdarg.h> .
size_t As described in <stddef.h> .

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

void clearerr(FILE *);

char *ctermid(char *);

int fclose(FILE *);

FILE *fdopen(int, const char *);

int feof(FILE *); int ferror(FILE *); int fflush(FILE *); int fgetc(FILE *); int fgetpos(FILE *restrict, fpos_t *restrict); char *fgets(char *restrict, int, FILE *restrict);

int fileno(FILE *);

void flockfile(FILE *);

FILE *fopen(const char *restrict, const char *restrict); int fprintf(FILE *restrict, const char *restrict, ...); int fputc(int, FILE *); int fputs(const char *restrict, FILE *restrict); size_t fread(void *restrict, size_t, size_t, FILE *restrict); FILE *freopen(const char *restrict, const char *restrict, FILE *restrict); int fscanf(FILE *restrict, const char *restrict, ...); int fseek(FILE *, long, int);

int fseeko(FILE *, off_t, int);

int fsetpos(FILE *, const fpos_t *); long ftell(FILE *);

off_t ftello(FILE *);

int ftrylockfile(FILE *); void funlockfile(FILE *);

size_t fwrite(const void *restrict, size_t, size_t, FILE *restrict); int getc(FILE *); int getchar(void);

int getc_unlocked(FILE *); int getchar_unlocked(void);

char *gets(char *);

int pclose(FILE *);

void perror(const char *);

FILE *popen(const char *, const char *);

int printf(const char *restrict, ...); int putc(int, FILE *); int putchar(int);

int putc_unlocked(int, FILE *); int putchar_unlocked(int);

int puts(const char *); int remove(const char *); int rename(const char *, const char *); void rewind(FILE *); int scanf(const char *restrict, ...); void setbuf(FILE *restrict, char *restrict); int setvbuf(FILE *restrict, char *restrict, int, size_t); int snprintf(char *restrict, size_t, const char *restrict, ...); int sprintf(char *restrict, const char *restrict, ...); int sscanf(const char *restrict, const char *restrict, int ...);

char *tempnam(const char *, const char *);

FILE *tmpfile(void); char *tmpnam(char *); int ungetc(int, FILE *); int vfprintf(FILE *restrict, const char *restrict, va_list); int vfscanf(FILE *restrict, const char *restrict, va_list); int vprintf(const char *restrict, va_list); int vscanf(const char *restrict, va_list); int vsnprintf(char *restrict, size_t, const char *restrict, va_list; int vsprintf(char *restrict, const char *restrict, va_list); int vsscanf(const char *restrict, const char *restrict, va_list arg);

Inclusion of the <stdio.h> header may also make visible all symbols from <stddef.h>.

The following sections are informative.








<stdarg.h> , <stddef.h> , <sys/types.h> , the System Interfaces volume of IEEE Std 1003.1-2001, clearerr(), ctermid(), fclose(), fdopen(), fgetc(), fgetpos(), ferror(), feof(), fflush(), fgets(), fileno(), flockfile(), fopen(), fputc(), fputs(), fread(), freopen(), fseek(), fsetpos(), ftell(), fwrite(), getc(), getc_unlocked(), getwchar(), getchar(), getopt(), gets(), pclose(), perror(), popen(), printf(), putc(), putchar(), puts(), putwchar(), remove(), rename(), rewind(), scanf(), setbuf(), setvbuf(), sscanf(), stdin, system(), tempnam(), tmpfile(), tmpnam(), ungetc(), vfscanf(), vscanf(), vprintf(), vsscanf()


Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at .

IEEE/The Open Group <stdio.h> (P) 2003
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