STRTOK(3) BSD Library Functions Manual STRTOK(3)
NAME
strtok, strtok_r -- string tokens
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <string.h>
char *
strtok(char *restrict str, const char *restrict sep);
char *
strtok_r(char *restrict str, const char *restrict sep, char **restrict lasts);
DESCRIPTION
This interface is obsoleted by strsep(3).
The strtok() function is used to isolate sequential tokens in a null-terminated string, str. These tokens are separated in the string by at
least one of the characters in sep. The first time that strtok() is called, str should be specified; subsequent calls, wishing to obtain
further tokens from the same string, should pass a null pointer instead. The separator string, sep, must be supplied each time, and may
change between calls.
The implementation will behave as if no library function calls strtok().
The strtok_r() function is a reentrant version of strtok(). The context pointer last must be provided on each call. The strtok_r() function
may also be used to nest two parsing loops within one another, as long as separate context pointers are used.
The strtok() and strtok_r() functions return a pointer to the beginning of each subsequent token in the string, after replacing the token
itself with a NUL character. When no more tokens remain, a null pointer is returned.
EXAMPLES
The following uses strtok_r() to parse two strings using separate contexts:
char test[80], blah[80];
char *sep = "\/:;=-";
char *word, *phrase, *brkt, *brkb;
strcpy(test, "This;is.a:test:of=the/string\tokenizer-function.");
for (word = strtok_r(test, sep, &brkt);
word;
word = strtok_r(NULL, sep, &brkt))
{
strcpy(blah, "blah:blat:blab:blag");
for (phrase = strtok_r(blah, sep, &brkb);
phrase;
phrase = strtok_r(NULL, sep, &brkb))
{
printf("So far we're at %s:%s
", word, phrase);
}
}
SEE ALSO
memchr(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3), wcstok(3)
STANDARDS
The strtok() function conforms to ISO/IEC 9899:1990 (``ISO C90'').
AUTHORS
Wes Peters, Softweyr LLC: <wes@softweyr.com>
Based on the FreeBSD 3.0 implementation.
BUGS
The System V strtok(), if handed a string containing only delimiter characters, will not alter the next starting point, so that a call to
strtok() with a different (or empty) delimiter string may return a non-NULL value. Since this implementation always alters the next starting
point, such a sequence of calls would always return NULL.
BSD
November 27, 1998 BSD