`_fread_nolock_s`

Article
04/12/2024

Reads data from a stream without locking. This version of fread_nolock has security enhancements, as described in Security features in the CRT.

Syntax

size_t _fread_nolock_s(
   void *buffer,
   size_t bufferSize,
   size_t elementSize,
   size_t elementCount,
   FILE *stream
);

Parameters

buffer
Storage location for data.

bufferSize
Size of the destination buffer in bytes.

elementSize
Size of the item to read in bytes.

elementCount
Maximum number of items to be read.

stream
Pointer to FILE structure.

Return value

See fread_s.

Remarks

This function is a non-locking version of fread_s. It's identical to fread_s except that it isn't protected from interference by other threads. It might be faster because it doesn't incur the overhead of locking out other threads. Use this function only in thread-safe contexts such as single-threaded applications or where the calling scope already handles thread isolation.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Function	Required header
`_fread_nolock_s`	C: <stdio.h>; C++: <cstdio> or <stdio.h>

For more compatibility information, see Compatibility.