NAME
strsep —
separate strings
SYNOPSIS
#include
<string.h>
char *
strsep(char
**stringp, const char
*delim);
DESCRIPTION
The
strsep()
function locates, in the 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.
EXAMPLES
The following uses strsep() to parse a
string, containing tokens delimited by whitespace, into an argument
vector:
char **ap, *argv[10], *inputstring;
for (ap = argv; ap < &argv[9] &&
(*ap = strsep(&inputstring, " \t")) != NULL;) {
if (**ap != '\0')
ap++;
}
*ap = NULL;
HISTORY
The strsep() function first appeared in
4.3BSD-Reno. It is intended as a replacement for the
strtok(3) function. While the
strtok(3) 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.