getc.3s

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3S 代码 · 共 86 行

.\" SCCSID: @(#)getc.3s	8.1	9/11/90
.TH getc 3s
.SH Name
getc, getchar, fgetc, getw \- get character or word from stream
.SH Syntax
.B #include <stdio.h>
.PP
.B int getc(stream)
.br
.SM
.B FILE
.B *stream;
.PP
.B int getchar()
.PP 
.B int fgetc(stream)
.br
.SM
.B FILE
.B *stream;
.PP
.B int getw(stream)
.br
.SM
.B FILE
.B *stream;
.SH Description
.NXR "getc subroutine (standard I/O)"
.NXR "getchar subroutine"
.NXR "fgetc subroutine (standard I/O)"
.NXR "getw subroutine"
.NXA "getc subroutine (standard I/O)" "unget subroutine"
.NXR "stream" "getting character from"
.NXR "stream" "getting word from"
The
.PN getc
function returns the next character from the named input
.IR stream .
.PP
The
.PN getchar
function 
is identical to 
.PN getc
(stdin).
.PP
The
.PN fgetc
function behaves like 
.PN getc ,
but is a genuine function, not a macro.
It may be used to save object text.
.PP
The
.PN getw
function returns the next
word (in a 32-bit integer on a VAX-11 or MIPS machine) from the named input
.IR stream .
It returns the constant EOF
upon end of file or error, but since that is a good
integer value,
.I feof
and
.MS ferror 3s
should be used to check the success of
.PN getw .
The
.PN getw
assumes no special alignment in the file.
.SH Restrictions
Because it is implemented as a macro,
.PN getc
treats a stream argument with side effects incorrectly.
In particular, `getc(*f++);' doesn't work as expected.
.SH Diagnostics
These functions return the integer constant EOF
at end of file or upon read error.
.PP
A stop with message,
`Reading bad file', means an attempt has been made to
read from a stream that has not been opened for
reading by
.PN fopen .
.SH See Also
fopen(3s), fread(3s), gets(3s), putc(3s), scanf(3s), ungetc(3s)