This function is similar to the strtok() function. The only key difference is that the _r, which is called as re-entrant function.
A re-entrant function is a function which can be interrupted during its execution. This type of function can be used to resume execution.
Because of this fact, re-entrant functions are thread-safe, means they can safely be interrupted by threads without any harm.
strtok_r() function has an extra parameter called the context. so that function can resume at the right place.
The syntax for strtok_r() function is as follows:
#include <string.h> char *strtok_r(char *string, const char *limiter, char **context);
Example
Following is the C program for the use of strtok_r() function −
#include <stdio.h>
#include <string.h>
int main(){
char input_string[] = "Hello Tutorials Point";
char token_list[20][20];
char* context = NULL;
char* token = strtok_r(input_string, " ", &context);
int num_tokens = 0; // Index to token list. We will append to the list
while (token != NULL){
strcpy(token_list[num_tokens], token); // Copy to token list
num_tokens++;
token = strtok_r(NULL, " ", &context);
}
// Print the list of tokens
printf("Token List:\n");
for (int i=0; i < num_tokens; i++) {
printf("%s\n", token_list[i]);
}
return 0;
}Output
When the above program is executed, it produces the following result −
Token List: Hello Tutorials Point