string.h File Reference

#include "stdint.h"
#include "stddef.h"

Go to the source code of this file.

Typedefs
typedef size_t	uint32_t
	Unsigned integral type. More...

Functions
void *	memcpy (void *destination, const void *source, size_t size)
	Copy block of memory. More...
void *	memmove (void *destination, const void *source, size_t size)
	Move block of memory. More...
char *	strcpy (char *destination, const char *source)
	Copy string. More...
char *	strncpy (char *destination, const char *source, size_t num)
	Copy characters from string. More...
char *	strcat (char *destination, const char *source)
	Concatenate strings. More...
char *	strncat (char *destination, const char *source, size_t num)
	Append characters from string. More...
int	memcmp (const void *buffer1, const void *buffer2, size_t size)
	Compare two blocks of memory. More...
int	strcmp (const char *str1, const char *str2)
	Compare two strings. More...
int	strcoll (const char *str1, const char *str2)
	Compare two strings using locale. More...
int	strncmp (const char *str1, const char *str2, size_t num)
	Compare two strings using locale. More...
size_t	strxfrm (char *destination, const char *source, size_t num)
	Transform string using locale. More...
void *	memchr (void *ptr, int value, size_t num)
	Locate character in block of memory. More...
char *	strchr (const char *str, int character)
	Locate first occurrence of character in string. More...
size_t	strcspn (const char *str1, const char *str2)
	Get span until character in string. More...
char *	strpbrk (char *str1, const char *str2)
	Locate characters in string. More...
char *	strrchr (char *str, int character)
	Locate last occurrence of character in string. More...
size_t	strspn (const char *str1, const char *str2)
	Get span of character set in string. More...
char *	strstr (const char *str1, const char *str2)
	Locate substring. More...
char *	strtok (char *str, const char *delimiters)
	Split string into tokens. More...
void *	memset (void *buffer, int value, size_t size)
	Fill block of memory. More...
char *	strerror (int errnum)
	Get pointer to error message string. More...
size_t	strlen (const char *str)
	Get string length. More...

Typedef Documentation

uint32_t

typedef size_t uint32_t

Unsigned integral type.

Function Documentation

memchr()

void* memchr	(	void *	ptr,
		int	value,
		size_t	num
	)

Locate character in block of memory.

Searches within the first num bytes of the block of memory pointed by ptr for the first occurrence of value (interpreted as an unsigned char), and returns a pointer to it.

Parameters

ptr	Pointer to the block of memory where the search is performed.
value	Value to be located. The value is passed as an int, but the function performs a byte per byte search using the unsigned char conversion of this value.
num	Number of bytes to be analyzed.

Returns

A pointer to the first occurrence of value in the block of memory pointed by ptr. If the value is not found, the function returns a null pointer.

memcmp()

int memcmp	(	const void *	buffer1,
		const void *	buffer2,
		size_t	size
	)

Compare two blocks of memory.

Compares the first num bytes of the block of memory pointed by ptr1 to the first num bytes pointed by ptr2, returning zero if they all match or a value different from zero representing which is greater if they do not.

Parameters

ptr1	Pointer to block of memory.
ptr2	Pointer to block of memory.
num	Number of bytes to compare.

Returns

Returns an integral value indicating the relationship between the content of the memory blocks (<0: value in ptr1 was lower than in ptr2, 0: both are equals, >0: value in ptr2 was greater than in ptr2).

memcpy()

void* memcpy	(	void *	destination,
		const void *	source,
		size_t	size
	)

Copy block of memory.

Copies the values of num bytes from the location pointed to by source directly to the memory block pointed to by destination.

Parameters

destination	Pointer to the destination array where the content is to be copied, type-casted to a pointer of type void*.
source	Pointer to the source of data to be copied, type-casted to a pointer of type const void*.
num	Number of bytes to copy.

Returns

Destination is returned.

memmove()

void* memmove	(	void *	destination,
		const void *	source,
		size_t	size
	)

Move block of memory.

Copies the values of num bytes from the location pointed by source to the memory block pointed by destination. Copying takes place as if an intermediate buffer were used, allowing the destination and source to overlap.

Parameters

destination	Pointer to the destination array where the content is to be copied, type-casted to a pointer of type void*.
source	Pointer to the source of data to be copied, type-casted to a pointer of type const void*.
num	Number of bytes to copy.

Returns

Destination is returned.

memset()

void* memset	(	void *	buffer,
		int	value,
		size_t	size
	)

Fill block of memory.

Sets the first num bytes of the block of memory pointed by ptr to the specified value (interpreted as an unsigned char).

Parameters

buffer	Pointer to the block of memory to fill.
value	Value to be set. The value is passed as an int, but the function fills the block of memory using the unsigned char conversion of this value.
size	Number of bytes to be set to the value.

Returns

Ptr is returned.

strcat()

char* strcat	(	char *	destination,
		const char *	source
	)

Concatenate strings.

Appends a copy of the source string to the destination string. The terminating null character in destination is overwritten by the first character of source, and a null-character is included at the end of the new string formed by the concatenation of both in destination.

Parameters

destination	Pointer to the destination array, which should contain a C string, and be large enough to contain the concatenated resulting string.
source	C string to be appended. This should not overlap destination.

Returns

Destination is returned.

strchr()

char* strchr	(	const char *	str,
		int	character
	)

Locate first occurrence of character in string.

Returns a pointer to the first occurrence of character in the C string str.

Parameters

str	C string.
character	Character to be located. It is passed as its int promotion, but it is internally converted back to char for the comparison.

Returns

A pointer to the first occurrence of value in the block of memory pointed by ptr. If the value is not found, the function returns a null pointer.

strcmp()

int strcmp	(	const char *	str1,
		const char *	str2
	)

Compare two strings.

Compares the C string str1 to the C string str2. This function starts comparing the first character of each string. If they are equal to each other, it continues with the following pairs until the characters differ or until a terminating null-character is reached.

Parameters

str1	C string to be compared.
str2	C string to be compared.

Returns

Returns an integral value indicating the relationship between the content of the memory blocks (<0: value in ptr1 was lower than in ptr2, 0: both are equals, >0: value in ptr2 was greater than in ptr2).

strcoll()

int strcoll	(	const char *	str1,
		const char *	str2
	)

Compare two strings using locale.

Compares the C string str1 to the C string str2, both interpreted appropriately according to the LC_COLLATE category of the C locale currently selected.

Parameters

str1	C string to be compared.
str2	C string to be compared.
num	Maximum number of characters to compare.

Returns

Returns an integral value indicating the relationship between the content of the memory blocks (<0: value in ptr1 was lower than in ptr2, 0: both are equals, >0: value in ptr2 was greater than in ptr2).

strcpy()

char* strcpy	(	char *	destination,
		const char *	source
	)

Copy string.

Copies the C string pointed by source into the array pointed by destination, including the terminating null character (and stopping at that point).

Parameters

destination	Pointer to the destination array where the content is to be copied.
source	C string to be copied.

Returns

Destination is returned.

strcspn()

size_t strcspn	(	const char *	str1,
		const char *	str2
	)

Get span until character in string.

Scans str1 for the first occurrence of any of the characters that are part of str2, returning the number of characters of str1 read before this first occurrence.

Parameters

str1	C string to be scanned.
str2	C string containing the characters to match.

Returns

The length of the initial part of str1 not containing any of the characters that are part of str2. This is the length of str1 if none of the characters in str2 are found in str1.

strerror()

char* strerror

(

int

errnum

)

Get pointer to error message string.

Interprets the value of errnum, generating a string with a message that describes the error condition as if set to errno by a function of the library.

Parameters

errnum

Error number.

Returns

A pointer to the error string describing error errnum.

strlen()

size_t strlen

(

const char *

str

)

Get string length.

Returns the length of the C string str. The length of a C string is determined by the terminating null-character.

Parameters

str

C string.

Returns

The length of string.

strncat()

char* strncat	(	char *	destination,
		const char *	source,
		size_t	num
	)

Append characters from string.

Appends the first num characters of source to destination, plus a terminating null-character.

Parameters

destination	Pointer to the destination array, which should contain a C string, and be large enough to contain the concatenated resulting string, including the additional null-character.
source	C string to be appended.
num	Maximum number of characters to be appended.

Returns

Destination is returned.

strncmp()

int strncmp	(	const char *	str1,
		const char *	str2,
		size_t	num
	)

Compare two strings using locale.

Compares up to num characters of the C string str1 to those of the C string str2.

Parameters

str1	C string to be compared.
str2	C string to be compared.

Returns

Returns an integral value indicating the relationship between the content of the memory blocks (<0: value in ptr1 was lower than in ptr2, 0: both are equals, >0: value in ptr2 was greater than in ptr2).

strncpy()

char* strncpy	(	char *	destination,
		const char *	source,
		size_t	num
	)

Copy characters from string.

Copies the first num characters of source to destination. If the end of the source C string (which is signaled by a null-character) is found before num characters have been copied, destination is padded with zeros until a total of num characters have been written to it.

Parameters

destination	Pointer to the destination array where the content is to be copied.
source	C string to be copied.
num	Maximum number of characters to be copied from source.

Returns

Destination is returned.

strpbrk()

char* strpbrk	(	char *	str1,
		const char *	str2
	)

Locate characters in string.

Returns a pointer to the first occurrence in str1 of any of the characters that are part of str2, or a null pointer if there are no matches.

Parameters

str1	C string to be scanned.
str2	C string containing the characters to match.

Returns

A pointer to the first occurrence in str1 of any of the characters that are part of str2, or a null pointer if none of the characters of str2 is found in str1 before the terminating null-character.

strrchr()

char* strrchr	(	char *	str,
		int	character
	)

Locate last occurrence of character in string.

Returns a pointer to the last occurrence of character in the C string str.

Parameters

str1	C string.
character	Character to be located. It is passed as its int promotion, but it is internally converted back to char.

Returns

A pointer to the last occurrence of character in str. If the character is not found, the function returns a null pointer.

strspn()

size_t strspn	(	const char *	str1,
		const char *	str2
	)

Get span of character set in string.

Returns the length of the initial portion of str1 which consists only of characters that are part of str2.

Parameters

str1	C string to be scanned.
str2	C string containing the characters to match.

Returns

The length of the initial portion of str1 containing only characters that appear in str2.

strstr()

char* strstr	(	const char *	str1,
		const char *	str2
	)

Locate substring.

Returns a pointer to the first occurrence of str2 in str1, or a null pointer if str2 is not part of str1.

Parameters

str1	C string to be scanned.
str2	C string containing the characters to match.

Returns

A pointer to the first occurrence in str1 of the entire sequence of characters specified in str2, or a null pointer if the sequence is not present in str1.

strtok()

char* strtok	(	char *	str,
		const char *	delimiters
	)

Split string into tokens.

A sequence of calls to this function split str into tokens, which are sequences of contiguous characters separated by any of the characters that are part of delimiters.

Parameters

str	C string to truncate.
delimeters	C string containing the delimiter characters.

Returns

If a token is found, a pointer to the beginning of the token. Otherwise, a null pointer.

strxfrm()

size_t strxfrm	(	char *	destination,
		const char *	source,
		size_t	num
	)

Transform string using locale.

Transforms the C string pointed by source according to the current locale and copies the first num characters of the transformed string to destination, returning its length.

Parameters

destinatino	Pointer to the destination array where the content is to be copied. It can be a null pointer if the argument for num is zero.
source	C string to be transformed.
num	Maximum number of characters to be copied to destination.

Returns

The length of the transformed string, not including the terminating null-character.