Man Rawmemchr en anglais
MEMCHR(3)                  Linux Programmer's Manual                 MEMCHR(3)



 

NAME


       memchr, memrchr, rawmemchr - scan memory for a character

 

SYNOPSIS


       #include 

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

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

       void *rawmemchr(const void *s, int c);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       rawmemchr(): _GNU_SOURCE

 

DESCRIPTION






       The  memchr()  function  scans  the  first  n  bytes of the memory area
       pointed to by s for the character c.  The first byte to match c (inter-
       preted as an unsigned character) stops the operation.

       The  memrchr()  function  is like the memchr() function, except that it
       searches backwards from the end of the n bytes pointed to by s  instead
       of forwards from the beginning.

       The  rawmemchr() function is similar to memchr(): it assumes (i.e., the
       programmer knows for certain) that the character c  lies  somewhere  in
       the  string  s, and so performs an optimized search for the character c
       (i.e., no checking for the terminating null byte, or use  of  an  argu-
       ment,  n,  to  limit the range of the search).  If the chararacter c is
       not in the string s, then rawmemchr() may proceeed to search beyond the
       end of the string, and the result is unspecified.  The folowing call is
       a fast means of locating a string's terminating null byte:

           char *p = rawmemchr(s, '\0');

 

RETURN VALUE


       The memchr() and memrchr() functions return a pointer to  the  matching
       byte  or NULL if the character does not occur in the given memory area.

       The rawmemchr() function returns a pointer to the matching byte, if one
       is found.  If no matching byte is found, the result is unspecified.

 

CONFORMING TO


       The memchr() function conforms to SVr4, 4.3BSD, C89, C99, POSIX.1-2001.

       The memrchr() function  is  a  GNU  extension,  available  since  glibc
       2.1.91.

       The rawmemchr() function is a GNU extension, available since glibc 2.1.

 

SEE ALSO


       index(3), rindex(3), strchr(3), strpbrk(3), strrchr(3), strsep(3), str-
       spn(3), strstr(3), wmemchr(3)

 

COLOPHON


       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2008-07-09                         MEMCHR(3)