memchr

 

C

Language

headers

Type support

Dynamic memory management

Error handling

Program utilities

Variadic function support

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

Technical Specifications

 

Strings library

Byte strings

Multibyte strings

Wide strings

 

Null-terminated byte strings

Functions
Character manipulation
isalnum isalpha islower isupper isdigit isxdigit isblank (C99)	iscntrl isgraph isspace isprint ispunct tolower toupper
Conversions to numeric formats
atof atoiatolatoll strtolstrtoll	strtoulstrtoull strtofstrtodstrtold strtoimaxstrtoumax (C99)(C99)
String manipulation
strcpystrcpy_s (C11)
strncpystrncpy_s (C11)
strcatstrcat_s (C11)
strncatstrncat_s (C11)
strxfrm
String examination
strlenstrnlen_s (C11) strcmp strncmp strcoll strchr strrchr	strspn strcspn strpbrk strstr strtokstrtok_s (C11)
Memory manipulation
memchr
memcmp
memsetmemset_s (C11)
memcpymemcpy_s (C11)
memmovememmove_s (C11)
Miscellaneous
strerrorstrerror_sstrerrorlen_s (C11)(C11)

 

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.

Parameters

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

Return value

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

Example

Run this code

#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

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

See also

strchr	finds the first occurrence of a character (function)
C++ documentation for memchr