136 lines
3.7 KiB
Groff
136 lines
3.7 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)strsep.3 8.1 (Berkeley) 6/9/93
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.\" $FreeBSD$
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.\"
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.Dd May 28, 2018
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.Dt STRSEP 3
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.Os
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.Sh NAME
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.Nm strsep
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.Nd separate strings
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In string.h
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.Ft char *
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.Fn strsep "char **stringp" "const char *delim"
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.Sh DESCRIPTION
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The
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.Fn strsep
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function locates, in the string referenced by
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.Fa *stringp ,
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the first occurrence of any character in the string
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.Fa delim
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(or the terminating
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.Ql \e0
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character) and replaces it with a
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.Ql \e0 .
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The location of the next character after the delimiter character
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(or NULL, if the end of the string was reached) is stored in
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.Fa *stringp .
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The original value of
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.Fa *stringp
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is returned.
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.Pp
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An
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.Dq empty
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field (i.e., a character in the string
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.Fa delim
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occurs as the first character of
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.Fa *stringp )
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can be detected by comparing the location referenced by the returned pointer
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to
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.Ql \e0 .
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.Pp
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If
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.Fa *stringp
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is initially
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.Dv NULL ,
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.Fn strsep
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returns
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.Dv NULL .
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.Sh EXAMPLES
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The following uses
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.Fn strsep
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to parse a string, and prints each token in separate line:
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.Bd -literal -offset indent
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char *token, *string, *tofree;
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tofree = string = strdup("abc,def,ghi");
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if (string == NULL)
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err(1, "strdup");
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while ((token = strsep(&string, ",")) != NULL)
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printf("%s\en", token);
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free(tofree);
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.Ed
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.Pp
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The following uses
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.Fn strsep
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to parse a string, containing tokens delimited by white space, into an
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argument vector:
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.Bd -literal -offset indent
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char **ap, *argv[10], *inputstring;
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for (ap = argv; (*ap = strsep(&inputstring, " \et")) != NULL;)
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if (**ap != '\e0')
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if (++ap >= &argv[10])
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break;
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.Ed
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.Sh SEE ALSO
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.Xr memchr 3 ,
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.Xr strchr 3 ,
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.Xr strcspn 3 ,
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.Xr strpbrk 3 ,
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.Xr strrchr 3 ,
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.Xr strspn 3 ,
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.Xr strstr 3 ,
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.Xr strtok 3
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.Sh HISTORY
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The
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.Fn strsep
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function
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is intended as a replacement for the
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.Fn strtok
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function.
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While the
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.Fn strtok
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function should be preferred for portability reasons (it conforms to
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.St -isoC )
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it is unable to handle empty fields, i.e., detect fields delimited by
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two adjacent delimiter characters, or to be used for more than a single
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string at a time.
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The
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.Fn strsep
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function first appeared in
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.Bx 4.4 .
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