FGETLK64

FGETLK64 is a system call in Unix-like operating systems, specifically found in Linux. It is used to get a record lock on a file or a portion of a file. The "64" in its name indicates that it operates on 64-bit file offsets, making it suitable for accessing very large files. This system call allows processes to coordinate access to shared data by preventing other processes from reading or writing to specific sections of a file while one process holds a lock.

The fgetlk64 function takes several arguments, including a file descriptor, the type of lock requested (read or write), and the starting offset and length of the region to be locked. It can also be used to test for the existence of a lock without blocking. If a requested lock cannot be granted immediately because another process holds a conflicting lock, fgetlk64 can either return an error or block the calling process until the lock becomes available, depending on the flags provided.

This system call is crucial for implementing reliable file sharing and synchronization mechanisms in multi-process environments. It helps prevent race conditions and data corruption that can occur when multiple processes attempt to modify the same file simultaneously. Applications that require robust file locking, such as databases, network file systems, and concurrent data processing tools, often utilize fgetlk64.