memory(3) [ultrix man page]
memory(3) Library Functions Manual memory(3) Name memccpy, memchr, memcmp, memcpy, memmove, memset - memory operations Syntax #include <string.h> void *memccpy (s1, s2, c, n) void *s1, *s2; int c; size_t n; void *memchr (s, c, n) void *s; int c; size_t n; int memcmp (s1, s2, n) void *s1, *s2; size_t n; void *memcpy (s1, s2, n) void *s1, *s2; size_t n; void *memset (s, c, n) void *s; int c; size_t n; void *memmove (s1, s2, n) void *s1, *s2; size_t n; Description These functions operate efficiently on memory areas (arrays of characters bounded by a count, not terminated by a null character). They do not check for the overflow of any receiving memory area. The subroutine copies characters from memory area s2 into s1, stopping after the first occurrence of character c has been copied, or after n characters have been copied, whichever comes first. It returns a pointer to the character after the copy of c in s1, or a NULL pointer if c was not found in the first n characters of s2. The subroutine returns a pointer to the first occurrence of character c in the first n characters of memory area s, or a NULL pointer if c does not occur. The subroutine compares its arguments, looking at the first n characters only, and returns an integer less than, equal to, or greater than 0, according as s1 is lexicographically less than, equal to, or greater than s2. The subroutine copies n characters from memory area s2 to s1. It returns s1. The subroutine is like , except that if s1 and s2 specify overlapping areas, works as if an intermediate buffer is used. The subroutine sets the first n characters in memory area s to the value of character c. It returns s. Restrictions The subroutine uses native character comparison, which is signed on PDP-11s, unsigned on other machines. Character movement is performed differently in different implementations of and Thus overlapping moves, using these subroutines, may yield unpredictable results. memory(3)
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memory(3C) Standard C Library Functions memory(3C) NAME
memory, memccpy, memchr, memcmp, memcpy, memmove, memset - memory operations SYNOPSIS
#include <string.h> void *memccpy(void *restrict s1, const void *restrict s2, int c, size_t n); void *memchr(const void *s, int c, size_t n); int memcmp(const void *s1, const void *s2, size_t n); void *memcpy(void *restrict s1, const void *restrict s2, size_t n); void *memmove(void *s1, const void *s2, size_t n); void *memset(void *s, int c, size_t n); ISO C++ #include <string.h> const void *memchr(const void *s, int c, size_t n); #include <cstring> void *std::memchr(void *s, int c, size_t n); DESCRIPTION
These functions operate as efficiently as possible on memory areas (arrays of bytes bounded by a count, not terminated by a null charac- ter). They do not check for the overflow of any receiving memory area. The memccpy() function copies bytes from memory area s2 into s1, stopping after the first occurrence of c (converted to an unsigned char) has been copied, or after n bytes have been copied, whichever comes first. It returns a pointer to the byte after the copy of c in s1, or a null pointer if c was not found in the first n bytes of s2. The memchr() function returns a pointer to the first occurrence of c (converted to an unsigned char) in the first n bytes (each interpreted as an unsigned char) of memory area s, or a null pointer if c does not occur. The memcmp() function compares its arguments, looking at the first n bytes (each interpreted as an unsigned char), and returns an integer less than, equal to, or greater than 0, according as s1 is lexicographically less than, equal to, or greater than s2 when taken to be unsigned characters. The memcpy() function copies n bytes from memory area s2 to s1. It returns s1. If copying takes place between objects that overlap, the behavior is undefined. The memmove() function copies n bytes from memory area s2 to memory area s1. Copying between objects that overlap will take place cor- rectly. It returns s1. The memset() function sets the first n bytes in memory area s to the value of c (converted to an unsigned char). It returns s. USAGE
Using memcpy() might be faster than using memmove() if the application knows that the objects being copied do not overlap. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
string(3C), attributes(5), standards(5) SunOS 5.10 1 Nov 2003 memory(3C)