strtoksr

strtoksr is a string tokenization function described as a reentrant, safer alternative to traditional strtok. It is designed to split a string into tokens using a set of delimiter characters, while avoiding the use of static internal state.

Interface and behavior: The function signature is commonly presented as char *strtoksr(char *str, const char *delims, char **context). The first call passes the input string in str; subsequent calls pass NULL for str to continue from the position saved in *context. It returns a pointer to the next token, or NULL when no tokens remain. Each token is a pointer into the original string, and the function inserts a null terminator after each token. Delimiter characters are any of the bytes present in delims.

Context management: The caller provides a per-call context object (a char* variable) that persists across calls. The function does not rely on static storage, enabling reentrancy and safer use in multithreaded environments. In concurrent code, each thread or task should maintain its own context.

Portability and variants: strtoksr is described as a cross-platform, reentrant variant of strtok. In practice, libraries differ in naming and parameter order (for example, strtok_r on POSIX and strtok_s on some platforms). If a library provides strtoksr, its exact signature and semantics should be verified in the local documentation.

Example: char s[] = "apple,banana,orange"; char *ctx = NULL; char *tok = strtoksr(s, ",", &ctx); while (tok != NULL) { /* process tok */ tok = strtoksr(NULL, ",", &ctx); }

See also: strtok, strtok_r, strtok_s.