String function

String functions as provided by string.h in the C standard library. More...

Functions
char *	strchrnul (const char *s, int c)
	Find the first occurrence of a character in a string.
char *	strchr (const char *s, int c)
	Find the first occurrence of a character in a string.
int	strcmp (const char *s1, const char *s2)
	Compare two strings.
int	strncmp (const char *s1, const char *s2, size_t n)
	Compare two strings.
size_t	strlen (const char *s)
	Calculate the length of a string.
size_t	strnlen (const char *s, size_t maxlen)
	Calculate the length of a string, limited by maxlen.
char *	strcpy (char *dest, const char *src)
	Copy the contents of a string including the terminating null byte (\0)
char *	strncpy (char *dest, const char *src, size_t n)
	Copy the contents of a string up to a maximum length or the terminating null byte (\0), whatever comes first.
void *	memcpy (void *__restrict__ dest, void const *__restrict__ src, size_t size)
	Copy a memory area.
void *	memmove (void *dest, void const *src, size_t size)
	Copy a memory area while the source may overlap with the destination.
void *	memset (void *dest, int pattern, size_t size)
	Fill a memory area with a pattern.
int	memcmp (const void *s1, const void *s2, size_t n)
	Compare a memory area.

Detailed Description

String functions as provided by string.h in the C standard library.

Function Documentation

strchrnul()

char * strchrnul	(	const char *	s,
		int	c
	)

Find the first occurrence of a character in a string.

Parameters

s	string to
c	character to find

Returns

Pointer to first occurrence of the character or to null byte at the end of the string if not found

strchr()

char * strchr	(	const char *	s,
		int	c
	)

Find the first occurrence of a character in a string.

Parameters

s	string to
c	character to find

Returns

Pointer to first occurrence of the character or to nullptr if not found

strcmp()

int strcmp	(	const char *	s1,
		const char *	s2
	)

Compare two strings.

Parameters

s1	first string
s2	second string

Returns

an integer less than, equal to, or greater than zero if first string is found, respectively, to be less than, to match, or be greater than second string

strncmp()

int strncmp	(	const char *	s1,
		const char *	s2,
		size_t	n
	)

Compare two strings.

Parameters

s1	first string
s2	second string
n	number of bytes to compare

Returns

an integer less than, equal to, or greater than zero if the given number of bytes of the first string are found, respectively, to be less than, to match, or be greater than second string

strlen()

size_t strlen

(

const char *

s

)

Calculate the length of a string.

Parameters

s	pointer to a string

Returns

number of bytes in the string

strnlen()

size_t strnlen	(	const char *	s,
		size_t	maxlen
	)

Calculate the length of a string, limited by maxlen.

Parameters

s	pointer to a string
maxlen	upper limit of length to be returned

Returns

number of bytes in the string, or maxlen – whichever is smaller

strcpy()

char * strcpy	(	char *	dest,
		const char *	src
	)

Copy the contents of a string including the terminating null byte (\0)

Parameters

dest	destination string buffer
src	source string buffer

Returns

a pointer to the destination string buffer

Note

Beware of buffer overruns!

strncpy()

char * strncpy	(	char *	dest,
		const char *	src,
		size_t	n
	)

Copy the contents of a string up to a maximum length or the terminating null byte (\0), whatever comes first.

Parameters

dest	destination string buffer
src	source string buffer
n	maximum number of bytes to copy

Returns

a pointer to the destination string buffer

Note

If there is no null byte (\0) among the first n bytes, the destination will not be null-terminated!

memcpy()

void * memcpy	(	void *__restrict__	dest,
		void const *__restrict__	src,
		size_t	size
	)

Copy a memory area.

Parameters

dest	destination buffer
src	source buffer
size	number of bytes to copy

Returns

pointer to destination

Note

The memory must not overlap!

memmove()

void * memmove	(	void *	dest,
		void const *	src,
		size_t	size
	)

Copy a memory area while the source may overlap with the destination.

Parameters

dest	destination buffer
src	source buffer
size	number of bytes to copy

Returns

pointer to destination

memset()

void * memset	(	void *	dest,
		int	pattern,
		size_t	size
	)

Fill a memory area with a pattern.

Parameters

dest	destination buffer
pattern	single byte pattern
size	number of bytes to fill with pattern

Returns

pointer to destination

memcmp()

int memcmp	(	const void *	s1,
		const void *	s2,
		size_t	n
	)

Compare a memory area.

Parameters

s1	first memory buffer
s2	second memory buffer
n	number of bytes to compare

Returns

an integer less than, equal to, or greater than zero if the first n bytes of s1 is found, respectively, to be less than, to match, or be greater than the first n bytes of s2.