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SK_PLUS_NetworkSemaphoreOpen Function

Keeps track of concurrent users of an application on a network by using semaphore files in a shared network location.

Remarks

A Network Semaphore File is a file, which contains no useful data, stored on a common network directory used to assist in enforcing a Network Floating License in an application. One file is created and locked exclusively for each active workstation or instance of your protected application. Other LAN users attempting to run the application will not be able to use any semaphore files that are locked, which is how this can enforce license compliance which limits the number of network "seats."

Any users who will use an application using this type of licensing will need access to read, write, modify, and delete the semaphore files.

This functionality is supported on environments where semaphore files are hosted on a Windows (SMB/CIFS) share, which functions best on a Local Area Network (LAN). While this may be used in a Wide Area Network (WAN) environment (which includes scenarios where a user access a given "LAN" over a Virtual Private Network [VPN] connection), it is strongly advised testing is done before deploying to any given WAN environment. This is because the performance of this feature is centered around that of the Windows (SMB/CIFS) shares being used to host the semaphore files (and WAN/VPN environments can see much slower performance than a typical LAN configuration).

With very large and/or WAN deployments, the performance degradation described above can often be avoided or limited by using the SK_FLAGS_NETWORK_SEMAPHORE_SKIPLOCKATTEMPT flag. This flag prevents this function from attempting to lock existing files (which it does to check if perhaps one of the existing files has been orphaned). While this flag can improve performance, keep in mind that using the flag also means you are required to call SK_PLUS_NetworkSemaphoreCleanup to delete orphaned semaphore files. If your application uses this flag without calling SK_PLUS_NetworkSemaphoreCleanup, it is likely that the presence of orphaned files will cause this function to prematurely return SK_ResultCode.SK_ERROR_NETWORK_LICENSE_FULL (meaning no seats are available).

Syntax

C/C++

SK_ResultCode SK_PLUS_NetworkSemaphoreOpen(SK_ApiContext context, int flags, int seatsAllowed, const char *seatsAllowedXPath, const char *semaphorePath, const char *semaphorePrefix, const char *optionalIdentifier, char **filePath);

Visual Basic

Declare Function SK_PLUS_NetworkSemaphoreOpen(ByVal context As Long, ByVal flags As Long, ByVal seatsAllowed As Long, ByVal seatsAllowedXPath As String, ByVal semaphorePath As String, ByVal semaphorePrefix As String, ByVal optionalIdentifier As String, ByRef filePath As String) As Long

Arguments

context

The API Context handle.

flags

Any flags passed into this function-call.

seatsAllowed

The maximum number of seats allowed. When seatsAllowedXPath is not null or empty, the specified license file value overrides this value.

seatsAllowedXPath

An XPath that specifies the license file property/field, which overrides the seatsAllowed parameter. If this parameter receives a null or empty string, the seatsAllowed value is used.

semaphorePath

The absolute path to the directory or network share where semaphore files will be created and locked. When using a network share, a UNC-formatted path is strongly recommended.

semaphorePrefix

The prefix to use for semaphore file names.

optionalIdentifier

Reserved for future use. Pass a null or empty string.

filePath

The path to the semaphore file which was created and locked.

Returns

All possible return values are included in the SK_ResultCode enumeration. Return codes to expect include: