strtok用法

char *  strtok ( char * string, const char * delimiters );

Sequentially truncate string if delimiter is found.
  If string is not NULL, the function scans string for the first occurrence of any character included in delimiters. If it is found, the function overwrites the delimiter in string by a null-character and returns a pointer to the token, i.e. the part of the scanned string previous to the delimiter.
  After a first call to strtok, the function may be called with NULL as string parameter, and it will follow by where the last call to strtok found a delimiter.
  delimiters may vary from a call to another.

Parameters.

string

Null-terminated string to scan.

separator

Null-terminated string containing the separators.

Return Value.
  A pointer to the last token found in string.   NULL is returned when there are no more tokens to be found.

Portability.
  Defined in ANSI-C.

Example.

/* strtok example */
#include <stdio.h>
#include <string.h>

int main ()
{
  char str[] ="This is a sample string,just testing.";
  char * pch;
  printf ("Splitting string \"%s\" in tokens:\n",str);
  pch = strtok (str," ");
  while (pch != NULL)
  {
    printf ("%s\n",pch);
    pch = strtok (NULL, " ,.");
  }
  return 0;
}

Output:
Splitting string "This is a sample string,just testing." in tokens:
This
is
a
sample
string
just
testing 

下面是linux下的strtok manual:
---------------------------------------------------------------
STRTOK(3)     Linux Programmer's Manual       STRTOK(3)

NAME
       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 \0 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  over-
       written with a \0 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() func-
       tion, 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),  str-
       spn(3), strstr(3)

GNU      2000-02-13        STRTOK(3)