STRSEP(3) BSD Programmer's Manual STRSEP(3)NAMEstrsep - 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 charac-
ters, 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 code fragment uses strsep() to parse a string, containing
tokens delimited by one or more white space characters, into an argument
vector:
char **ap, *argv[10], *inputstring;
for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)
if (**ap != '\0')
++ap;
Deleting the line:
if (**ap != '\0')
would change the code to include empty fields in the argument vector.
HISTORY
The strsep() function is intended as a replacement for the strtok() func-
tion. While the strtok() function should be preferred for portability
reasons (it conforms to ANSI C X3.159-1989 (``ANSI C '')) it is unable to
handle empty fields, i.e. detect fields delimited by two adjacent delim-
iter characters, or to be used for more than a single string at a time.
The strsep() function first appeared in 4.4BSD.
BSDI BSD/OS June 9, 1993 1
