###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_strnstr Search a string, up to n bytes, for the first instance of a specific substring. ## Header File Defined in [<SDL3/SDL_stdinc.h>](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_stdinc.h) ## Syntax ```c char * SDL_strnstr(const char *haystack, const char *needle, size_t maxlen); ``` ## Function Parameters | | | | | ------------ | ------------ | ---------------------------------------------------- | | const char * | **haystack** | the string to search. Must not be NULL. | | const char * | **needle** | the string to search for. Must not be NULL. | | size_t | **maxlen** | the maximum number of bytes to search in `haystack`. | ## Return Value (char *) Returns a pointer to the first instance of `needle` in the string, or NULL if not found. ## Remarks The search ends once it finds the requested substring, or a null terminator byte to end the string, or `maxlen` bytes have been examined. It is possible to use this function on a string without a null terminator. Note that this looks for strings of _bytes_, not _characters_, so it's legal to search for malformed and incomplete UTF-8 sequences. ## Thread Safety It is safe to call this function from any thread. ## Version This function is available since SDL 3.1.3. ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryStdinc](CategoryStdinc)