[#BloombergLP-bdls-FilesystemUtil-tryLock]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bdls.adoc[bdls]::xref:BloombergLP/bdls/FilesystemUtil.adoc[FilesystemUtil]::tryLock
:relfileprefix: ../../../
:mrdocs:

Acquire a lock for the file with `descriptor` if it is available.

== Synopsis

Declared in `<bdls_filesystemutil.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
int
tryLock(
    xref:BloombergLP/bdls/FilesystemUtil/FileDescriptor.adoc[FileDescriptor] descriptor,
    bool lockWriteFlag);
----

== Description

Acquire a lock for the file with the specified `descriptor` if it is currently available. If the specified `lockWriteFlag` is true, acquire an exclusive write lock unless another process has any type of lock on the file. If `lockWriteFlag` is false, acquire a shared read lock unless a process has a write lock. This method will not block. Return 0 on success, `k_ERROR_LOCKING_CONFLICT` if the platform reports the lock could not be acquired because another process holds a conflicting lock, and a negative value for any other kind of error. Note that this operation locks the indicated file for the current _process_, but the behavior is unspecified (and platform‐dependent) when either attempting to lock `descriptor` multiple times, or attempting to lock another descriptor referring to the same file, within a single process.

== Return Value

0 on success, `k_ERROR_LOCKING_CONFLICT` on a conflicting lock, and a negative value for any other error

== Parameters

[cols="1,4"]
|===
| Name| Description
| *descriptor*
| file descriptor of the file to lock
| *lockWriteFlag*
| `true` for an exclusive write lock; `false` for a shared read lock
|===


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