[unix-history] / man / fopen.u

.TH FOPEN UCB 4/8/79
.SH NAME
fopen, freopen \- open a stream
.SH SYNOPSIS
.B #include <nstdio.h>
.PP
.SM
.B FILE
.B *fopen(filename, type)
.br
.B char *filename, *type;
.PP
.SM
.B FILE
.B *freopen(filename, type, stream)
.br
.B char *filename, *type;
.br
.SM
.B FILE
.B *stream;
.SH DESCRIPTION
.I Fopen
opens the file named by
.I filename
and associates a stream with it.
.I Fopen
returns a pointer to be used to identify
the stream in subsequent operations.
.PP
.I Type
is a character string having one of the following values:
.TP 5
"r"
open for reading
.ns
.TP 5
"w"
create for writing
.ns
.TP 5
"rw"
create for concurrent read/write access
.ns
.TP 5
"a"
append: open for writing at end
of file, or create for writing
.ns
.TP 5
"ra"
read and append: open for concurrent read/write access  at end
of file, or create file and open with such access
.PP
.I Freopen
substitutes the named file in place
of the open
.IR stream .
It returns the original value of
.IR stream .
The original stream is closed.
.PP
.I Freopen
is typically used to attach the preopened
constant names,
.B stdin, stdout, stderr,
to specified files.
.SH "SEE ALSO"
open(2),
fclose(3)
.SH DIAGNOSTICS
.I Fopen
and 
.I freopen
return the pointer
.SM
.B NULL
if
.I filename
cannot be accessed.
.SH BUGS
Undoubtedly
Commit	Line	Data
d38390b9 BJ	1	.TH FOPEN UCB 4/8/79
	2	.SH NAME
	3	fopen, freopen \- open a stream
	4	.SH SYNOPSIS
	5	.B #include <nstdio.h>
	6	.PP
	7	.SM
	8	.B FILE
	9	.B *fopen(filename, type)
	10	.br
	11	.B char filename, type;
	12	.PP
	13	.SM
	14	.B FILE
	15	.B *freopen(filename, type, stream)
	16	.br
	17	.B char filename, type;
	18	.br
	19	.SM
	20	.B FILE
	21	.B *stream;
	22	.SH DESCRIPTION
	23	.I Fopen
	24	opens the file named by
	25	.I filename
	26	and associates a stream with it.
	27	.I Fopen
	28	returns a pointer to be used to identify
	29	the stream in subsequent operations.
	30	.PP
	31	.I Type
	32	is a character string having one of the following values:
	33	.TP 5
	34	"r"
	35	open for reading
	36	.ns
	37	.TP 5
	38	"w"
	39	create for writing
	40	.ns
	41	.TP 5
	42	"rw"
	43	create for concurrent read/write access
	44	.ns
	45	.TP 5
	46	"a"
	47	append: open for writing at end
	48	of file, or create for writing
	49	.ns
	50	.TP 5
	51	"ra"
	52	read and append: open for concurrent read/write access at end
	53	of file, or create file and open with such access
	54	.PP
	55	.I Freopen
	56	substitutes the named file in place
	57	of the open
	58	.IR stream .
	59	It returns the original value of
	60	.IR stream .
	61	The original stream is closed.
	62	.PP
	63	.I Freopen
	64	is typically used to attach the preopened
65	constant names,
66	.B stdin, stdout, stderr,
67	to specified files.
68	.SH "SEE ALSO"
69	open(2),
70	fclose(3)
71	.SH DIAGNOSTICS
72	.I Fopen
73	and
74	.I freopen
75	return the pointer
76	.SM
77	.B NULL
78	if
79	.I filename
80	cannot be accessed.
81	.SH BUGS
82	Undoubtedly