Manual Pages for UNIX Operating System command usage for man memset

Standard C Library Functions                           memory(3C)



NAME
     memory, memccpy, memchr, memcmp,  memcpy,  memmove,  memset,
     memmem - memory operations

SYNOPSIS
     #include 

     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);


     void *memmem(const void *haystack, size_t haystacklen, const void *needle,
          size_t needlelen);


  ISO C++
     #include 

     const void *memchr(const void *s, int c, size_t n);


     #include 

     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 character). 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



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Standard C Library Functions                           memory(3C)



     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 correctly. 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.


     The  memmem()  function  locates  the  start  of  the  first
     occurrence  of  the  substring needle of length needlelen in
     the memory area haystack of length haystacklen. It returns a
     pointer  to  the start of the substring, or NULL if the sub-
     string is not found.

USAGE
     Using memcpy() might be faster than using memmove()  if  the
     application knows that the objects being copied do not over-
     lap.

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:









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Standard C Library Functions                           memory(3C)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|
    | Standard                    | See standards(5).           |
    |_____________________________|_____________________________|


SEE ALSO
     string(3C), attributes(5), standards(5)

NOTES
     Overlap between objects being copied  can  arise  even  when
     their  (virtual)  address  ranges appear to be disjoint; for
     example, as a result of memory-mapping overlapping  portions
     of the same underlying file, or of attaching the same shared
     memory segment more than once.



































SunOS 5.11          Last change: 11 Oct 2010                    3