Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

strtok_r(3) [netbsd man page]

STRTOK(3)						   BSD Library Functions Manual 						 STRTOK(3)

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

Check Out this Related Man Page

STRTOK(3)						     Linux Programmer's Manual							 STRTOK(3)

strtok, strtok_r - extract tokens from strings SYNOPSIS
#include <string.h> char *strtok(char *s, const char *delim); char *strtok_r(char *s, const char *delim, char **ptrptr); DESCRIPTION
A `token' is a nonempty string of characters not occurring in the string delim, followed by or by a character occurring in delim. The strtok() function can be used to parse the string s into tokens. The first call to strtok() should have s as its first argument. Subse- quent calls should have the first argument set to NULL. Each call returns a pointer to the next token, or NULL when no more tokens are found. If a token ends with a delimiter, this delimiting character is overwritten with a and a pointer to the next character is saved for the next call to strtok(). The delimiter string delim may be different for each call. The strtok_r() function is a reentrant version of the strtok() function, which instead of using its own static buffer, requires a pointer to a user allocated char*. This pointer, the ptrptr parameter, must be the same while parsing the same string. BUGS
Never use these functions. If you do, note that: These functions modify their first argument. These functions cannot be used on constant strings. The identity of the delimiting character is lost. The strtok() function uses a static buffer while parsing, so it's not thread safe. Use strtok_r() if this matters to you. RETURN VALUE
The strtok() function returns a pointer to the next token, or NULL if there are no more tokens. CONFORMING TO
strtok() SVID 3, POSIX, BSD 4.3, ISO 9899 strtok_r() POSIX.1c SEE ALSO
index(3), memchr(3), rindex(3), strchr(3), strpbrk(3), strsep(3), strspn(3), strstr(3) GNU
2000-02-13 STRTOK(3)
Man Page