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Searches within the first num bytes of the block of memory pointed by ptr for the first occurrence of value (interpreted as an unsigned char), and returns a pointer to it.
Both value and each of the bytes checked on the the ptr array are interpreted as unsigned char for the comparison.
If the value is not found, the function returns a null pointer.
instead of the two overloaded versions provided in C++.
Output:
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
function
<cstring>
memchr
const void * memchr ( const void * ptr, int value, size_t num ); void * memchr ( void * ptr, int value, size_t num );
Locate character in block of memory
Both value and each of the bytes checked on the the ptr array are interpreted as unsigned char for the comparison.
Parameters
- ptr
- Pointer to the block of memory where the search is performed.
- value
- Value to be located. The value is passed as an int, but the function performs a byte per byte search using the unsigned char conversion of this value.
- num
- Number of bytes to be analyzed.
size_t is an unsigned integral type.
Return Value
A pointer to the first occurrence of value in the block of memory pointed by ptr.If the value is not found, the function returns a null pointer.
Portability
In C, this function is only declared as:void * memchr ( const void *, int, size_t ); instead of the two overloaded versions provided in C++.
Example
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Output:
'p' found at position 5. |
See also
- memcmp
- Compare two blocks of memory (function)
- strchr
- Locate first occurrence of character in string (function)
- strrchr
- Locate last occurrence of character in string (function)
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Spotted an error? contact us