Find the next token in a string.
char *strtok( char *strToken, const char *strDelimit );
wchar_t *wcstok( wchar_t *strToken, const wchar_t *strDelimit );
unsigned char *_mbstok( unsigned char*strToken, const unsigned char *strDelimit );
| Routine | Required Header | Compatibility |
| strtok | <string.h> | ANSI, Win 95, Win NT |
| wcstok | <string.h> or <wchar.h> | ANSI, Win 95, Win NT |
| _mbstok | <mbstring.h> | Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
All of these functions return a pointer to the next token found in strToken. They return NULL when no more tokens are found. Each call modifies strToken by substituting a NULL character for each delimiter that is encountered.
Parameters
strToken
String containing token(s)
strDelimit
Set of delimiter characters
Remarks
The strtok function finds the next token in strToken. The set of characters in strDelimit specifies possible delimiters of the token to be found in strToken on the current call. wcstok and _mbstok are wide-character and multibyte-character versions of strtok. The arguments and return value of wcstok are wide-character strings; those of _mbstok are multibyte-character strings. These three functions behave identically otherwise.
Generic-Text Routine Mappings
| TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
| _tcstok | strtok | _mbstok | wcstok |
On the first call to strtok, the function skips leading delimiters and returns a pointer to the first token in strToken, terminating the token with a null character. More tokens can be broken out of the remainder of strToken by a series of calls to strtok. Each call to strtok modifies strToken by inserting a null character after the token returned by that call. To read the next token from strToken, call strtok with a NULL value for the strToken argument. The NULL strToken argument causes strtok to search for the next token in the modified strToken. The strDelimit argument can take any value from one call to the next so that the set of delimiters may vary.
Warning Each of these functions uses a static variable for parsing the string into tokens. If multiple or simultaneous calls are made to the same function, a high potential for data corruption and inaccurate results exists. Therefore, do not attempt to call the same function simultaneously for different strings and be aware of calling one of these function from within a loop where another routine may be called that uses the same function. However, calling this function simultaneously from multiple threads does not have undesirable effects.
Example
/* STRTOK.C: In this program, a loop uses strtok
* to print all the tokens (separated by commas
* or blanks) in the string named "string".
*/
#include <string.h>
#include <stdio.h>
char string[] = "A string\tof ,,tokens\nand some more tokens";
char seps[] = " ,\t\n";
char *token;
void main( void )
{
printf( "%s\n\nTokens:\n", string );
/* Establish string and get the first token: */
token = strtok( string, seps );
while( token != NULL )
{
/* While there are tokens in "string" */
printf( " %s\n", token );
/* Get next token: */
token = strtok( NULL, seps );
}
}
Output
A string of ,,tokens
and some more tokens
Tokens:
A
string
of
tokens
and
some
more
tokens