V10/man/man3/getc.3

.TH GETC 3S
.CT 2 file_io
.SH NAME
getc, getchar, fgetc, getw, putc, putchar, fputc, putw  \(mi character- or word-at-a-time stream input/output
.SH SYNOPSIS
.2C
.nf
.B #include <stdio.h>
.PP
.B int getc(stream)
.B FILE *stream;
.PP
.B int getchar()
.PP
.B int getw(stream)
.B FILE *stream;
.PP
.B int fgetc(stream)
.B FILE *stream;
.PP
.B int putc(c, stream)
.B char c;
.B FILE *stream;
.PP
.B putchar(c)
.PP
.B putw(w, stream)
.B FILE *stream;
.PP
.B fputc(c, stream)
.B FILE *stream;
.1C
.fi
.SH DESCRIPTION
.I Getc
returns the next character from the named input
.IR stream .
.PP
.IR Getchar ()
is identical to
.IR getc ( stdin ).
.PP
.I Getw
returns the next
word (32-bit integer on a VAX) from the named input
.IR stream .
.I Getw
assumes no special alignment in the file.
.PP
.I Putc
appends the character
.I c
to the named output
.IR stream .
It returns the character written.
.PP
.IR Putchar ( c )
is identical to
.IR putc ( "c, stdout" ).
.PP
.I Putw
appends word
(i.e.\&
.BR int )
.I w
to the output
.IR stream .
It returns the word written.
.I Putw
neither assumes nor causes special alignment in the file.
.PP
.I Fgetc
and
.I fputc
behave like
.I getc
and
.I putc,
but are genuine functions, not  macros;
they may be used to save object text.
.PP
The standard output stream
.B stdout
is normally buffered,
but is flushed whenever 
.IR getc
causes a buffer to be refilled from
.BR stdin .
The standard error stream
.B stderr
is normally unbuffered.
These defaults may be changed by
.IR setbuf (3).
When an output stream is unbuffered, information appears on the
destination file or terminal as soon as written.
When an output stream is buffered, many characters are saved up and written as a block.
.I Fflush
may be used to force the block out early; see
.IR fopen (3).
.SH "SEE ALSO"
.IR fopen (3),
.IR ungetc (3),
.IR stdio (3)
.SH DIAGNOSTICS
These functions return the integer constant
.B EOF
at end of file or error.
For
.I getw
or
.I putw
this indication is ambiguous;
.IR  ferror (3)
may be used to distinguish.
.SH BUGS
Because they are implemented as macros,
.I getc
and
.I putc
treat
.I stream
arguments with side effects incorrectly.
For example,
.B getc(*f++)
is wrong.
.br
The routines in
.IR printf (3)
provide temporary buffering
even when buffering has been turned off.
.br
Write errors may be delayed until a subsequent
.I stdio (3)
writing, seeking, or file-closing call.