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       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.

              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(),


       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 .