strtok_r, from Berkeley strtok
Oct 13, 1998 by Wes Peters <wes@softweyr.com>
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@(#)strtok.3 8.2 (Berkeley) 2/3/94
$FreeBSD: releng/10.3/lib/libc/string/strtok.3 295350 2016-02-06 14:03:31Z wblock $
.Dd January 22, 2016 .Dt STRTOK 3 .Os .Sh NAME .Nm strtok , strtok_r .Nd string tokens .Sh LIBRARY .Lb libc .Sh SYNOPSIS n string.h .Ft char * .Fn strtok "char *str" "const char *sep" .Ft char * .Fn strtok_r "char *str" "const char *sep" "char **last" .Sh DESCRIPTION f -symbolic This interface is obsoleted by .Xr strsep 3 . .Ef
p The .Fn strtok function is used to isolate sequential tokens in a null-terminated string, .Fa str . These tokens are separated in the string by at least one of the characters in .Fa sep . The first time that .Fn strtok is called, .Fa str should be specified; subsequent calls, wishing to obtain further tokens from the same string, should pass a null pointer instead. The separator string, .Fa sep , must be supplied each time, and may change between calls.
p The implementation will behave as if no library function calls .Fn strtok .
p The .Fn strtok_r function is a reentrant version of .Fn strtok . The context pointer .Fa last must be provided on each call. The .Fn strtok_r function may also be used to nest two parsing loops within one another, as long as separate context pointers are used.
p The .Fn strtok and .Fn strtok_r functions return a pointer to the beginning of each subsequent token in the string, after replacing the token itself with a .Dv NUL character. When no more tokens remain, a null pointer is returned. .Sh EXAMPLES The following uses .Fn strtok_r to parse two strings using separate contexts: d -literal char test[80], blah[80]; char *sep = "\e\e/:;=-"; char *word, *phrase, *brkt, *brkb; strcpy(test, "This;is.a:test:of=the/string\e\etokenizer-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\en", word, phrase); } } .Ed .Sh SEE ALSO .Xr memchr 3 , .Xr strchr 3 , .Xr strcspn 3 , .Xr strpbrk 3 , .Xr strrchr 3 , .Xr strsep 3 , .Xr strspn 3 , .Xr strstr 3 , .Xr wcstok 3 .Sh STANDARDS The .Fn strtok function conforms to .St -isoC . The .Fn strtok_r function conforms to .St -p1003.1-2001 . .Sh AUTHORS .An Wes Peters , Softweyr LLC: .Aq wes@softweyr.com
p Based on the .Fx 3.0 implementation. .Sh BUGS The System V .Fn strtok , if handed a string containing only delimiter characters, will not alter the next starting point, so that a call to .Fn strtok with a different (or empty) delimiter string may return a
f non- Dv NULL value. Since this implementation always alters the next starting point, such a sequence of calls would always return .Dv NULL .