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.
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.

Detailed Description

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

Function Documentation

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

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

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

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

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!

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

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

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!