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)