strtok(3)                                                     strtok(3)

  strtok()

  NAME

    strtok(), strtok_r() - string tokens

  SYNOPSIS

    #include 

    char * strtok (char *str, const char *sep)
    char * strtok_r (char *str, const char *sep,
           char **lasts)

  DESCRIPTION

    The strtok(3) 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(3) 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(3) function returns 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.

    The reentrant strtok_r(3) function assumes that the null-terminated string
    identified by the str argument is a sequence of zero or more text tokens
    separated by spans of one or more characters from the separator string
    identified by the sep argument. The argument lasts points to a user-
    provided pointer that points to stored information necessary for
    strtok_r(3) to continue scanning the same string.

    In the first call to strtok_r(3), str points to a null-terminated string,
    sep points to a null-terminated string of separator characters, and lasts
    is ignored. The strtok_r(3) function returns a pointer to the first
    character of the first token, writes a null character into str immediately
    following the returned token, and updates the pointer to which lasts
    points.

    In subsequent calls, str is a NULL pointer and lasts is unchanged from the
    previous call so that subsequent calls move through the string str,
    returning successive tokens until no tokens remain. The separator string
    sep can be different from call to call. When no token remains in str, a
    NULL pointer is returned.

  SEE ALSO

    memchr(3)

    strchr(3)

    strcspn(3)

    strpbrk(3)

    strrchr(3)

    strsep(3)

    strspn(3)

    strstr(3)

  USAGE NOTES

    The strtok_r function is thread safe. The strtok function is not thread
    safe.

    None of these functions are async-signal safe.