STRSEP(3)

NAME
strsep - separate strings

LIBRARY
libc

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., 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.

EXAMPLES
The following uses strsep() to parse a string, and prints each token in separate line:

    char *token, *string, *tofree;
    tofree = string = strdup("abc,def,ghi");
    if (string == NULL)
    	err(1, "strdup");
    while ((token = strsep(&string, ",")) != NULL)
    	printf("%s\n", token);
    free(tofree);

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 = strsep(&inputstring, " \t")) != NULL;)
    	if (**ap != '\0')
    		if (++ap >= &argv[10])
    			break;

SEE ALSO
memchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strspn(3), strstr(3), strtok(3)

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 isoC) 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.