strtok

 

C

Language

Standard Library

Type support

Dynamic memory management

Error handling

Program utilities

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

 

Strings library

Byte strings

Multibyte strings

Wide strings

 

Null-terminated byte strings

Functions
Character manipulation
isalnum isalpha islower isupper isdigit isxdigit isblank (C++11)	iscntrl isgraph isspace isprint ispunct tolower toupper
Conversions to numeric formats
atof atoi atol atoll strtol strtoll	strtoul strtoull strtof strtod strtold
String manipulation
strcpy
strncpy
strcat
strncat
strxfrm
String examination
strlen strcmp strncmp strcoll strchr strrchr	strspn strcspn strpbrk strstr strtok
Memory manipulation
memchr
memcmp
memset
memcpy
memmove
Miscellaneous
strerror

 

Defined in header <string.h>
char *strtok( char          *str, const char          *delim );		(until C99)
char *strtok( char *restrict str, const char *restrict delim );		(since C99)

Finds the next token in a null-terminated byte string pointed to by str. The separator characters are identified by null-terminated byte string pointed to by delim.

This function is designed to be called multiples times to obtain successive tokens from the same string.

• If str != NULL, the call is treated as the first call to strtok for this particular string. The function searches for the first character which is not contained in delim.

• If no such character was found, there are no tokens in str at all, and the function returns a null pointer.
• If such character was found, is it the beginning of the token. The function then searches from that point on for the first character that is contained in delim.

• If no such character was found, str has only one token, and the future calls to strtok will return a null pointer
• If such character was found, it is replaced by the null character '\0' and the pointer to the following character is stored in a static location for subsequent invocations.

• The function then returns the pointer to the beginning of the token

• If str == NULL, the call is treated as a subsequent calls to strtok: the function continues from where it left in previous invocation. The behavior is the same as if the previously stored pointer is passed as str.

Parameters

str	-	pointer to the null-terminated byte string to tokenize
delim	-	pointer to the null-terminated byte string identifying delimiters

Return value

Pointer to the beginning of the next token or NULL if there are no more tokens.

Note

This function is destructive: it writes the '\0' characters in the elements of the string str. In particular, a string literal cannot be used as the first argument of strtok.

Each call to this function modifies a static variable: is not thread safe.