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memchr

From natekohl.net
< c‎ | string‎ | byte
Defined in header <string.h>
void* memchr( const void* ptr, int ch, size_t count );

Finds the first occurrence of ch (after conversion to unsigned char as if by (unsigned char)ch) in the initial count characters (each interpreted as unsigned char) of the object pointed to by ptr.

The behavior is undefined if access occurs beyond the end of the array searched. The behavior is undefined if ptr is a null pointer.

This function behaves as if it reads the characters sequentially and stops as soon as a matching character is found: if the array pointed to by ptr is smaller than count, but the match is found within the array, the behavior is well-defined

(since C11)

Contents

[edit] Parameters

ptr - pointer to the object to be examined
ch - character to search for
count - max number of characters to examine

[edit] Return value

Pointer to the location of the character, or NULL if no such character is found.

[edit] Example

#include <stdio.h>
#include <string.h>
 
int main(void)
{
    char str[] = "ABCDEFG";
    char *ps = memchr(str,'D',strlen(str));
    if (ps != NULL)
       printf ("search character found:  %s\n", ps);
    else
       printf ("search character not found\n");
 
    return 0;
}

Output:

search character found:  DEFG

[edit] References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.24.5.1 The memchr function (p: 367)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.21.5.1 The memchr function (p: 330)
  • C89/C90 standard (ISO/IEC 9899:1990):
  • 4.11.5.1 The memchr function

[edit] See also

finds the first occurrence of a character
(function) [edit]