NAME
strsep,
stresep —
separate strings
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strsep(
char
**stringp,
const char
*delim);
char *
stresep(
char
**stringp,
const char
*delim,
int escape);
DESCRIPTION
The
strsep() function locates, in the nul-terminated string
referenced by
*stringp, the first occurrence of any
character in the string
delim (or the terminating
‘
\0
’ character) and replaces it with a
‘
\0
’. The location of the next character
after the delimiter character (or
NULL
, if the end of
the string was reached) is stored in
*stringp. The
original value of
*stringp is returned.
An “empty” field, i.e., one caused by two adjacent delimiter
characters, can be detected by comparing the location referenced by the
pointer returned by
strsep() to
‘
\0
’.
If
*stringp is initially
NULL
,
strsep() returns
NULL
. The
stresep() function also takes an escape character that
allows quoting the delimiter character so that it can be part of the source
string.
EXAMPLES
The following uses
strsep() to parse a string, containing
tokens delimited by white space, into an argument vector:
char **ap, *argv[10], *inputstring;
for (ap = argv; ap < &argv[9] &&
(*ap = strsep(&inputstring, " \t")) != NULL;) {
if (**ap != '\0')
ap++;
}
HISTORY
The
strsep() function is intended as a replacement for the
strtok() function. While the
strtok()
function should be preferred for portability reasons (it conforms to
ANSI X3.159-1989 (“ANSI C89”)) it is
unable to handle empty fields, i.e., detect fields delimited by two adjacent
delimiter characters, or to be used for more than a single string at a time.
The
strsep() function first appeared in
4.4BSD.