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strtok(3) [freebsd man page]

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 *str, const char *sep); char * strtok_r(char *str, const char *sep, char **last); 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 <wes@softweyr.com>, Softweyr LLC 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

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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 *str, const char *sep, char **lasts); DESCRIPTION
The strtok() function is used to isolate sequential tokens in a nul-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 strtok() function returns a pointer to the beginning of each subsequent token in the string, after replacing the separator character itself with a NUL character. Separator characters at the beginning of the string or at the continuation point are skipped so that zero length tokens are not returned. When no more tokens remain, a null pointer is returned. The strtok_r() function implements the functionality of strtok() but is passed an additional argument, lasts, which points to a user-provided pointer which is used by strtok_r() to store state which needs to be kept between calls to scan the same string; unlike strtok(), it is not necessary to limit tokenizing to a single string at a time when using strtok_r(). EXAMPLES
The following will construct an array of pointers to each individual word in the string s: #define MAXTOKENS 128 char s[512], *p, *tokens[MAXTOKENS]; char *last; int i = 0; snprintf(s, sizeof(s), "cat dog horse cow"); for ((p = strtok_r(s, " ", &last)); p; (p = strtok_r(NULL, " ", &last)), i++) { if (i < MAXTOKENS - 1) tokens[i] = p; } tokens[i] = NULL; That is, tokens[0] will point to "cat", tokens[1] will point to "dog", tokens[2] will point to "horse", and tokens[3] will point to "cow". SEE ALSO
index(3), memchr(3), rindex(3), strchr(3), strcspn(3), strpbrk(3), strrchr(3), strsep(3), strspn(3), strstr(3) STANDARDS
The strtok() function conforms to ANSI X3.159-1989 (``ANSI C89''). The strtok_r() function conforms to IEEE Std 1003.1c-1995 (``POSIX.1''). 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
August 11, 2002 BSD

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