- 1 Does strtok return a string?
- 2 What is the difference between strtok and Strtok_r?
- 3 Is strtok thread safe?
- 4 How does strtok work in C?
- 5 When should you not use strtok?
- 6 Does strtok free memory?
- 7 How to store the returned values from strtok?
- 8 Why does strtok ( ) keep parsing the string?
- 9 Is there an error when calling strtok ( )?
- 10 Where does strtok ( ) get the pointer from?
Does strtok return a string?
Returned value In later calls with the same token string, strtok() returns a pointer to the next token in the string. A NULL pointer is returned when there are no more tokens. All tokens are NULL-terminated.
What is the difference between strtok and Strtok_r?
strtok save static pointer for reuse in the next time, when you give NULL as the first parameter, so you just can’t parse 2 strings in parallel. In the strtok_r you give also the pointer, as out parameter (pointer to pointer).
Is strtok thread safe?
The strtok() function uses a static buffer while parsing, so it’s not thread safe.
How does strtok work in C?
The first time the strtok() function is called, it returns a pointer to the first token in string1. In later calls with the same token string, the strtok() function returns a pointer to the next token in the string. A NULL pointer is returned when there are no more tokens. All tokens are null-ended.
When should you not use strtok?
strtok is neither thread safe nor re-entrant because it uses a static buffer while parsing. This means that if a function calls strtok , no function that it calls while it is using strtok can also use strtok , and it cannot be called by any function that is itself using strtok .
Does strtok free memory?
3 Answers. strtok manipulates the string you pass in and returns a pointer to it, so no memory is allocated.
How to store the returned values from strtok?
If you want to store the returned values from strtok you need to copy the token to another buffer e.g. strdup (p); since the original string (pointed to by the static pointer inside strtok) is modified between iterations in order to return the token.
Why does strtok ( ) keep parsing the string?
The key to the operation of strtok () is preserving the location of the last seperator between seccessive calls (that’s why strtok () continues to parse the very original string that is passed to it when it is invoked with a null pointer in successive calls)..
Is there an error when calling strtok ( )?
One more problem of using strtok () is that as it stores the address in static variables , in multithreaded programming calling strtok () more than once will cause an error. For this use strtok_r (). you can scan the char array looking for the token if you found it just print new line else print the char.
Where does strtok ( ) get the pointer from?
strtok() stores the pointer in static variable where did you last time left off , so on its 2nd call , when we pass the null , strtok() gets the pointer from the static variable . If you provide the same string name , it again starts from beginning.