STRTOK

Section: Linux Programmer's Manual (3 )
Updated: 2000-02-13
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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:

These functions modify their first argument.

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

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