STRTOK(3) | Linux Programmer's Manual | STRTOK(3) |
NAME¶
strtok, strtok_r - extract tokens from strings
SYNOPSIS¶
#include <string.h> char *strtok(char *s, const char *delim); char *strtok_r(char *s, const char *delim, char **ptrptr);
DESCRIPTION¶
A `token' is a nonempty string of characters not occurring in the string delim, followed by \0 or by a character occurring in delim.
The strtok() function can be used to parse the string s into tokens. The first call to strtok() should have s as its first argument. Subsequent calls should have the first argument set to NULL. Each call returns a pointer to the next token, or NULL when no more tokens are found.
If a token ends with a delimiter, this delimiting character is overwritten with a \0 and a pointer to the next character is saved for the next call to strtok(). The delimiter string delim may be different for each call.
The strtok_r() function works the same as the strtok() function, but instead of using a static buffer it uses a pointer to a user allocated char* pointer. This pointer, the ptrptr parameter, must be the same while parsing the same string.
BUGS¶
Never use these functions. If you do, note that:
The identity of the delimiting character is lost.
These functions cannot be used on constant strings.
The strtok() function uses a static buffer while parsing, so it's not thread safe. Use strtok_r() if this matters to you.
RETURN VALUE¶
The strtok() function returns a pointer to the next token, or NULL if there are no more tokens.
CONFORMING TO¶
- strtok()
- SVID 3, POSIX, BSD 4.3, ISO 9899
- strtok_r()
- POSIX.1c
SEE ALSO¶
index(3), memchr(3), rindex(3), strchr(3), strpbrk(3), strsep(3), strspn(3), strstr(3)
February 13, 2000 | GNU |