STRTOK(3) Linux Programmer's Manual STRTOK(3) NAME strtok, strtok_r - extract tokens from strings SYNOPSIS #include <string.h> char *strtok(char *str, const char *delim); char *strtok_r(char *str, const char *delim, char **saveptr); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): strtok_r(): _SVID_SOURCE || _BSD_SOURCE || _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_SOURCE DESCRIPTION The strtok() function parses a string into a sequence of tokens. On the first call to strtok() the string to be parsed should be specified in str. In each subsequent call that should parse the same string, str should be NULL. The delim argument specifies a set of characters that delimit the tokens in the parsed string. The caller may specify different strings in delim in successive calls that parse the same string. Each call to strtok() returns a pointer to a null-terminated string containing the next token. This string does not include the delimiting character. If no more tokens are found, strtok() returns NULL. A sequence of two or more contiguous delimiter characters in the parsed string is considered to be a single delimiter. Delimiter characters at the start or end of the string are ignored. Put another way: the tokens returned by strtok() are always non-empty strings. The strtok_r() function is a reentrant version strtok(). The saveptr argument is a pointer to a char * variable that is used internally by strtok_r() in order to maintain context between successive calls that parse the same string. On the first call to strtok_r(), str should point to the string to be parsed, and the value of saveptr is ignored. In subsequent calls, str should be NULL, and saveptr should be unchanged since the previous call. Different strings may be parsed concurrently using sequences of calls to strtok_r() that specify different saveptr arguments. RETURN VALUE The strtok() and strtok_r() functions return a pointer to the next token, or NULL if there are no more tokens. CONFORMING TO strtok() SVr4, POSIX.1-2001, 4.3BSD, C89, C99. strtok_r() POSIX.1-2001. BUGS Use these functions. If you do use them, note that: These functions modify their first argument. These functions cannot be used on constant strings. The identity of the delimiting character is lost. The strtok() function uses a static buffer while parsing.