ftrylockfile(3S)

ftrylockfile -- grant thread ownership of a file

Synopsis

#include <stdio.h>

int ftrylockfile(FILE

file);

Description

This function provide for explicit application-level locking of standard I/O objects. It can be used by a thread to begin a sequence of I/O statements that are to be executed as a unit.

ftrylockfile gives the calling thread ownership of file if file is not currently owned by another thread. This function is similar to flockfile, except that it returns nonzero if the file is already locked. It returns zero on success.

A thread can do multiple calls to ftrylockfile and flockfile successfully if it currently owns the file, but an equal number of funlockfile calls are necessary to relinquish the object completely.

Return values

On success, ftrylockfile returns zero and locks the stream file. If the stream is already locked by a different thread, it returns nonzero.

References

flock(3S), flockfile(3S), funlockfile(3S), Intro(3S)