[thirdparty/man-pages.git] / man3 / fpathconf.3

.\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\" 
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\" 
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" License.
.\" Modified Wed Jul 28 11:12:26 1993 by Rik Faith (faith@cs.unc.edu)
.TH FPATHCONF 3  1993-04-04 "GNU" "Linux Programmer's Manual"
.SH NAME
fpathconf, pathconf \- get configuration values for files
.SH SYNOPSIS
.nf
.B #include <unistd.h>
.sp
.BI "long fpathconf(int " filedes ", int " name );
.nl
.BI "long pathconf(char *" path ", int " name );
.fi
.SH DESCRIPTION
.B fpathconf()
gets a value for the configuration option
.I name
for the open file descriptor
.IR filedes .
.PP
.B pathconf()
gets a value for configuration option
.I name
for the file name
.IR path .
.PP
The corresponding macros defined in
.B <unistd.h>
are minimum values; if an application wants to take advantage of values
which may change, a call to
.B fpathconf()
or
.B pathconf()
can be made, which may yield more liberal results.
.PP
Setting
.I name
equal to one of the following constants returns the following
configuration options:
.TP
.B _PC_LINK_MAX
returns the maximum number of links to the file.  If
.I filedes
or
.I path
refer to a directory, then the value applies to the whole directory.
The corresponding macro is
.BR _POSIX_LINK_MAX .
.TP
.B _PC_MAX_CANON
returns the maximum length of a formatted input line, where
.I filedes
or
.I path
must refer to a terminal.
The corresponding macro is
.BR _POSIX_MAX_CANON .
.TP
.B _PC_MAX_INPUT
returns the maximum length of an input line, where
.I filedes
or
.I path
must refer to a terminal.
The corresponding macro is
.BR _POSIX_MAX_INPUT .
.TP
.B _PC_NAME_MAX
returns the maximum length of a filename in the directory
.I path
or
.IR filedes .
the process is allowed to create.
The corresponding macro is
.BR _POSIX_NAME_MAX .
.TP
.B _PC_PATH_MAX
returns the maximum length of a relative pathname when
.I path
or
.I filedes
is the current working directory.  The corresponding macro is
.BR _POSIX_PATH_MAX .
.TP
.B _PC_PIPE_BUF
returns the size of the pipe buffer, where
.I filedes
must refer to a pipe or FIFO and
.I path
must refer to a FIFO. The corresponding macro is
.BR _POSIX_PIPE_BUF .
.TP
.B _PC_CHOWN_RESTRICTED
returns non-zero if the
.BR chown (2)
call may not be used on this file.  If
.I filedes
or
.I path
refer to a directory, then this applies to all files in that
directory.  The corresponding macro is
.BR _POSIX_CHOWN_RESTRICTED .
.TP
.B _PC_NO_TRUNC
returns non-zero if accessing filenames longer than
.B _POSIX_NAME_MAX
generates an error.  The corresponding macro is
.BR _POSIX_NO_TRUNC .
.TP
.B _PC_VDISABLE
returns non-zero if special character processing can be disabled, where
.I filedes
or
.I path
must refer to a terminal.
.SH "RETURN VALUE"
The limit is returned, if one exists.  If the system does not have a
limit for the requested resource, \-1 is returned, and
.I errno
is unchanged.  If there is an error, \-1 is returned, and
.I errno
is set to reflect the nature of the error.
.SH "CONFORMING TO"
POSIX.1
.SH NOTES
Files with name lengths longer than the value returned for
.I name
equal to
.B _PC_NAME_MAX
may exist in the given directory.
.PP
Some returned values may be huge; they are not suitable for allocating
memory.
.SH "SEE ALSO"
.BR getconf (1),
.BR open (2),
.BR statfs (2),
.BR sysconf (3)
Commit	Line	Data
fea681da MK	1	.\" (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
	2	.\"
	3	.\" Permission is granted to make and distribute verbatim copies of this
	4	.\" manual provided the copyright notice and this permission notice are
	5	.\" preserved on all copies.
	6	.\"
	7	.\" Permission is granted to copy and distribute modified versions of this
	8	.\" manual under the conditions for verbatim copying, provided that the
	9	.\" entire resulting derived work is distributed under the terms of a
	10	.\" permission notice identical to this one.
	11	.\"
	12	.\" Since the Linux kernel and libraries are constantly changing, this
	13	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	14	.\" responsibility for errors or omissions, or for damages resulting from
	15	.\" the use of the information contained herein. The author(s) may not
	16	.\" have taken the same level of care in the production of this manual,
	17	.\" which is licensed free of charge, as they might when working
	18	.\" professionally.
	19	.\"
	20	.\" Formatted or processed versions of this manual, if unaccompanied by
	21	.\" the source, must acknowledge the copyright and authors of this work.
	22	.\" License.
	23	.\" Modified Wed Jul 28 11:12:26 1993 by Rik Faith (faith@cs.unc.edu)
	24	.TH FPATHCONF 3 1993-04-04 "GNU" "Linux Programmer's Manual"
	25	.SH NAME
	26	fpathconf, pathconf \- get configuration values for files
	27	.SH SYNOPSIS
	28	.nf
	29	.B #include <unistd.h>
	30	.sp
	31	.BI "long fpathconf(int " filedes ", int " name );
	32	.nl
	33	.BI "long pathconf(char *" path ", int " name );
	34	.fi
	35	.SH DESCRIPTION
	36	.B fpathconf()
	37	gets a value for the configuration option
	38	.I name
	39	for the open file descriptor
	40	.IR filedes .
	41	.PP
	42	.B pathconf()
	43	gets a value for configuration option
	44	.I name
	45	for the file name
	46	.IR path .
	47	.PP
	48	The corresponding macros defined in
	49	.B <unistd.h>
	50	are minimum values; if an application wants to take advantage of values
	51	which may change, a call to
	52	.B fpathconf()
	53	or
	54	.B pathconf()
	55	can be made, which may yield more liberal results.
	56	.PP
	57	Setting
	58	.I name
	59	equal to one of the following constants returns the following
	60	configuration options:
	61	.TP
	62	.B _PC_LINK_MAX
	63	returns the maximum number of links to the file. If
	64	.I filedes
65	or
66	.I path
67	refer to a directory, then the value applies to the whole directory.
68	The corresponding macro is
69	.BR _POSIX_LINK_MAX .
70	.TP
71	.B _PC_MAX_CANON
72	returns the maximum length of a formatted input line, where
73	.I filedes
74	or
75	.I path
76	must refer to a terminal.
77	The corresponding macro is
78	.BR _POSIX_MAX_CANON .
79	.TP
80	.B _PC_MAX_INPUT
81	returns the maximum length of an input line, where
82	.I filedes
83	or
84	.I path
85	must refer to a terminal.
86	The corresponding macro is
87	.BR _POSIX_MAX_INPUT .
88	.TP
89	.B _PC_NAME_MAX
90	returns the maximum length of a filename in the directory
91	.I path
92	or
93	.IR filedes .
94	the process is allowed to create.
95	The corresponding macro is
96	.BR _POSIX_NAME_MAX .
97	.TP
98	.B _PC_PATH_MAX
99	returns the maximum length of a relative pathname when
100	.I path
101	or
102	.I filedes
103	is the current working directory. The corresponding macro is
104	.BR _POSIX_PATH_MAX .
105	.TP
106	.B _PC_PIPE_BUF
107	returns the size of the pipe buffer, where
108	.I filedes
109	must refer to a pipe or FIFO and
110	.I path
111	must refer to a FIFO. The corresponding macro is
112	.BR _POSIX_PIPE_BUF .
113	.TP
114	.B _PC_CHOWN_RESTRICTED
f59a3f19	115	returns non-zero if the
fea681da MK	116	.BR chown (2)
	117	call may not be used on this file. If
	118	.I filedes
	119	or
	120	.I path
	121	refer to a directory, then this applies to all files in that
	122	directory. The corresponding macro is
	123	.BR _POSIX_CHOWN_RESTRICTED .
	124	.TP
	125	.B _PC_NO_TRUNC
f59a3f19	126	returns non-zero if accessing filenames longer than
fea681da MK	127	.B _POSIX_NAME_MAX
	128	generates an error. The corresponding macro is
	129	.BR _POSIX_NO_TRUNC .
	130	.TP
	131	.B _PC_VDISABLE
f59a3f19	132	returns non-zero if special character processing can be disabled, where
fea681da MK	133	.I filedes
	134	or
	135	.I path
	136	must refer to a terminal.
	137	.SH "RETURN VALUE"
	138	The limit is returned, if one exists. If the system does not have a
	139	limit for the requested resource, \-1 is returned, and
	140	.I errno
	141	is unchanged. If there is an error, \-1 is returned, and
	142	.I errno
	143	is set to reflect the nature of the error.
	144	.SH "CONFORMING TO"
	145	POSIX.1
	146	.SH NOTES
	147	Files with name lengths longer than the value returned for
	148	.I name
	149	equal to
	150	.B _PC_NAME_MAX
	151	may exist in the given directory.
	152	.PP
	153	Some returned values may be huge; they are not suitable for allocating
	154	memory.
	155	.SH "SEE ALSO"
	156	.BR getconf (1),
	157	.BR open (2),
	158	.BR statfs (2),
	159	.BR sysconf (3)