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version 2003
PA_LockResource (resfile; kind; resID) 
char
| Parameter | Type | Description | |
| resfile | short | | File reference number of the file to access |
| kind | unsigned long | | Kind (4 Bytes type) of resource to access |
| resID | short | | Unique resource ID |
| Function result | char |  | 1 = The resource has been locked. 0 = Already in use |
Description
The routine PA_LockResource tries to lock the resource of type kind and the ID resID of the file resFile over the network; it returns 1 if successfully locked, and 0 if the resource is already in use by an other client.
You should always lock the resource before modifying it so that no one can modify it while you read or modify it. Once a resource is locked, it can not be modified by another process and it can neither be disposed or nor purged from memory.
If the resource does not exist or if resFile is an invalid file reference number, the routine does nothing and PA_GetLastError returns -5 ("Resource not found").
It is not necessary to lock the resource if the plug-in only wants to read it.
WARNING
In 4D single-user, the routine always returns 1. It is the plug-in's responsibility to manage multiprocess access in this case.
Example
Lock the resource 'pipf' ID 128.
typedef struct {
short f1;
short f2;
long f3;
/* ... */
}PLUG_PREFS;
// Lock the resource
if( PA_LockResource(resFile, 'pipf', 128))
{
// Ok, no one can modify it on an other machine
// Initialize one structure
PLUG_PREFS h = {1, 2, 3};
// Change the resource content
PA_SetResource(resFile, 'pipf', 128, (char *) &prefs, sizeof(PLUG_PREFS));
//write the resource
PA_Write(resFile)
// Unlock it
PA_Unlockresource(resFile, 'pipf', 128);
}
See Also
About the internal resource manager, PA_GetResource, PA_UnlockResource.
Error Handling
Use PA_GetLastError to see if an error occurred
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