#include <strings.h>
char *strtok (
char *s1,
const char *s2
)
|
Arguments
|
s1 |
Pointer to target character string to search |
| s2 |
Pointer to character set containing token delimiters |
Return Value
A pointer to the first character of a token is returned, or NULL is returned
if there is no token.
Explanation
A sequence of calls to strtok() breaks the string pointed to by
s1 into a sequence of tokens, each of which is delimited by a character
from the string pointed to by s2. The first call in the sequence
has s1 as its first argument, and is followed by calls with a NULL
pointer as their first argument. The first call in the sequence searches
the string pointed to by s1 for the first character that is not
contained in the current separator string pointed to by s2. If no
such character is found, then there are no tokens in the string pointed
to by s1 and the function returns a NULL pointer. If such a character
is found, it is the start of the first token. strtok() then searches
from there for a character that is contained in the current separator string.
If no such character is found, the current token extends to the end of
the string pointed to by s1, and subsequent searches for a token
will return a NULL pointer. If such a character is found, it is overwritten
by a NULL character, which terminates the current token. strtok()
saves a pointer to the following character, from which the next search
for a token will start. Each subsequent call, with a NULL pointer as the
value of the first argument, starts searching from the saved pointer and
behaves as described above.
|