[apple/libc.git] / util / fparseln.3

.\"	$NetBSD: fparseln.3,v 1.7 1999/07/02 15:49:12 simonb Exp $
.\" $FreeBSD: src/lib/libutil/fparseln.3,v 1.9 2001/10/01 16:09:18 ru Exp $
.\"
.\" Copyright (c) 1997 Christos Zoulas.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by Christos Zoulas.
.\" 4. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd December 1, 1997
.Dt FPARSELN 3
.Os
.Sh NAME
.Nm fparseln
.Nd return the next logical line from a stream
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdio.h
.In util.h
.Ft "char *"
.Fo fparseln
.Fa "FILE *stream" "size_t *len" "size_t *lineno"
.Fa "const char delim[3]" "int flags"
.Fc
.Sh DESCRIPTION
The
.Fn fparseln
function
returns a pointer to the next logical line from the stream referenced by
.Fa stream .
This string is
.Dv NUL
terminated and it is dynamically allocated on each invocation.
It is the
responsibility of the caller to free the pointer.
.Pp
By default, if a character is escaped, both it and the preceding escape
character will be present in the returned string.
Various
.Fa flags
alter this behaviour.
.Pp
The meaning of the arguments is as follows:
.Bl -tag -width "lineno"
.It Fa stream
The stream to read from.
.It Fa len
If not
.Dv NULL ,
the length of the string is stored in the memory location to which it
points.
.It Fa lineno
If not
.Dv NULL ,
the value of the memory location to which is pointed to, is incremented
by the number of lines actually read from the file.
.It Fa delim
Contains the escape, continuation, and comment characters.
If a character is
.Dv NUL
then processing for that character is disabled.
If
.Dv NULL ,
all characters default to values specified below.
The contents of
.Fa delim
is as follows:
.Bl -tag -width "delim[0]"
.It Fa delim[0]
The escape character, which defaults to
.Cm \e ,
is used to remove any special meaning from the next character.
.It Fa delim[1]
The continuation character, which defaults to
.Cm \e ,
is used to indicate that the next line should be concatenated with the
current one if this character is the last character on the current line
and is not escaped.
.It Fa delim[2]
The comment character, which defaults to
.Cm # ,
if not escaped indicates the beginning of a comment that extends until the
end of the current line.
.El
.It Fa flags
If non-zero, alter the operation of
.Fn fparseln .
The various flags, which may be
.Em or Ns -ed
together, are:
.Bl -tag -width "FPARSELN_UNESCCOMM"
.It Dv FPARSELN_UNESCCOMM
Remove escape preceding an escaped comment.
.It Dv FPARSELN_UNESCCONT
Remove escape preceding an escaped continuation.
.It Dv FPARSELN_UNESCESC
Remove escape preceding an escaped escape.
.It Dv FPARSELN_UNESCREST
Remove escape preceding any other character.
.It Dv FPARSELN_UNESCALL
All of the above.
.El
.Pp
.El
.Sh RETURN VALUES
Upon successful completion a pointer to the parsed line is returned;
otherwise,
.Dv NULL
is returned.
.Pp
The
.Fn fparseln
function uses internally
.Xr fgetln 3 ,
so all error conditions that apply to
.Xr fgetln 3 ,
apply to
.Fn fparseln .
In addition
.Fn fparseln
may set
.Va errno
to
.Er ENOMEM
and return
.Dv NULL
if it runs out of memory.
.Sh SEE ALSO
.Xr fgetln 3
.Sh HISTORY
The
.Fn fparseln
function first appeared in
.Nx 1.4 .
Commit	Line	Data
9385eb3d A	1	.\" $NetBSD: fparseln.3,v 1.7 1999/07/02 15:49:12 simonb Exp $
	2	.\" $FreeBSD: src/lib/libutil/fparseln.3,v 1.9 2001/10/01 16:09:18 ru Exp $
	3	.\"
	4	.\" Copyright (c) 1997 Christos Zoulas. All rights reserved.
	5	.\"
	6	.\" Redistribution and use in source and binary forms, with or without
	7	.\" modification, are permitted provided that the following conditions
	8	.\" are met:
	9	.\" 1. Redistributions of source code must retain the above copyright
	10	.\" notice, this list of conditions and the following disclaimer.
	11	.\" 2. Redistributions in binary form must reproduce the above copyright
	12	.\" notice, this list of conditions and the following disclaimer in the
	13	.\" documentation and/or other materials provided with the distribution.
	14	.\" 3. All advertising materials mentioning features or use of this software
	15	.\" must display the following acknowledgement:
	16	.\" This product includes software developed by Christos Zoulas.
	17	.\" 4. The name of the author may not be used to endorse or promote products
	18	.\" derived from this software without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	21	.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	22	.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	23	.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	24	.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	25	.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	26	.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	27	.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	28	.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	29	.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	30	.\"
	31	.Dd December 1, 1997
	32	.Dt FPARSELN 3
	33	.Os
	34	.Sh NAME
	35	.Nm fparseln
	36	.Nd return the next logical line from a stream
	37	.Sh LIBRARY
	38	.Lb libc
	39	.Sh SYNOPSIS
	40	.In stdio.h
	41	.In util.h
	42	.Ft "char *"
	43	.Fo fparseln
	44	.Fa "FILE stream" "size_t len" "size_t *lineno"
	45	.Fa "const char delim[3]" "int flags"
	46	.Fc
	47	.Sh DESCRIPTION
	48	The
	49	.Fn fparseln
	50	function
	51	returns a pointer to the next logical line from the stream referenced by
	52	.Fa stream .
	53	This string is
	54	.Dv NUL
	55	terminated and it is dynamically allocated on each invocation.
	56	It is the
	57	responsibility of the caller to free the pointer.
	58	.Pp
	59	By default, if a character is escaped, both it and the preceding escape
	60	character will be present in the returned string.
	61	Various
	62	.Fa flags
	63	alter this behaviour.
	64	.Pp
65	The meaning of the arguments is as follows:
66	.Bl -tag -width "lineno"
67	.It Fa stream
68	The stream to read from.
69	.It Fa len
70	If not
71	.Dv NULL ,
72	the length of the string is stored in the memory location to which it
73	points.
74	.It Fa lineno
75	If not
76	.Dv NULL ,
77	the value of the memory location to which is pointed to, is incremented
78	by the number of lines actually read from the file.
79	.It Fa delim
80	Contains the escape, continuation, and comment characters.
81	If a character is
82	.Dv NUL
83	then processing for that character is disabled.
84	If
85	.Dv NULL ,
86	all characters default to values specified below.
87	The contents of
88	.Fa delim
89	is as follows:
90	.Bl -tag -width "delim[0]"
91	.It Fa delim[0]
92	The escape character, which defaults to
93	.Cm \e ,
94	is used to remove any special meaning from the next character.
95	.It Fa delim[1]
96	The continuation character, which defaults to
97	.Cm \e ,
98	is used to indicate that the next line should be concatenated with the
99	current one if this character is the last character on the current line
100	and is not escaped.
101	.It Fa delim[2]
102	The comment character, which defaults to
103	.Cm # ,
104	if not escaped indicates the beginning of a comment that extends until the
105	end of the current line.
106	.El
107	.It Fa flags
108	If non-zero, alter the operation of
109	.Fn fparseln .
110	The various flags, which may be
111	.Em or Ns -ed
112	together, are:
113	.Bl -tag -width "FPARSELN_UNESCCOMM"
114	.It Dv FPARSELN_UNESCCOMM
115	Remove escape preceding an escaped comment.
116	.It Dv FPARSELN_UNESCCONT
117	Remove escape preceding an escaped continuation.
118	.It Dv FPARSELN_UNESCESC
119	Remove escape preceding an escaped escape.
120	.It Dv FPARSELN_UNESCREST
121	Remove escape preceding any other character.
122	.It Dv FPARSELN_UNESCALL
123	All of the above.
124	.El
125	.Pp
126	.El
127	.Sh RETURN VALUES
128	Upon successful completion a pointer to the parsed line is returned;
129	otherwise,
130	.Dv NULL
131	is returned.
132	.Pp
133	The
134	.Fn fparseln
135	function uses internally
136	.Xr fgetln 3 ,
137	so all error conditions that apply to
138	.Xr fgetln 3 ,
139	apply to
140	.Fn fparseln .
141	In addition
142	.Fn fparseln
143	may set
144	.Va errno
145	to
146	.Er ENOMEM
147	and return
148	.Dv NULL
149	if it runs out of memory.
150	.Sh SEE ALSO
151	.Xr fgetln 3
152	.Sh HISTORY
153	The
154	.Fn fparseln
155	function first appeared in
156	.Nx 1.4 .