strsep -- separate strings
Standard C Library (libc, -lc)
strsep(char **stringp, const char *delim);
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., a character in the string delim occurs as the
first character of *stringp) can be detected by comparing the location
referenced by the returned pointer to `\0'.
If *stringp is initially NULL, strsep() returns NULL.
The following uses strsep() to parse a string, containing tokens delimited
by white space, into an argument vector:
char **ap, *argv, *inputstring;
for (ap = argv; (*ap = strsep(&inputstring, " \t")) != NULL;)
if (**ap != '\0')
if (++ap >= &argv)
memchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strspn(3),
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 ISO/IEC 9899:1990 (``ISO 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.
FreeBSD 5.2.1 June 9, 1993 FreeBSD 5.2.1 [ Back ]