2 Visual Components Manuals

VC_HANDLE if 0 then
ready = 1
endif
endif
if ready = 1 then
if VA_Saccess(1,VC_HANDLE)= 0 then
....
....
endif
endif
3.3.8.22.3 Example for C Programming
#include
#include
#include
UINT _GLOBAL ready;
unsigned long VC_HANDLE;
_CYCLIC void Cyclic(void)
{
if (!ready)
{
VC_HANDLE = VA_Setup(1 "vga"); ,
if (VC_HANDLE)
ready = 1;
}
if (ready)
{
if (!VA_Saccess(1,VC_HANDLE))
{
....
....
}
}
}
Here are some typical errors associated with VA_Saccess and VA_Srelease:
• VA_Saccess(1, VC_HANDLE);
VA_Line(1,VC_HANDLE, 10, 10, 100, 100, 1);
VA_Srelease(1,VC_HANDLE);
This is incorrect! VA_Srelease is called even if VA_Saccess fails.
• ...
...
if (VA_Saccess(1,VC_HANDLE) == ERR_OK)
{
VA_Line(1,VC_HANDLE, 10, 10, 100, 100, 1);
}
...
...
This is incorrect! VA_Srelease has been left out.
• CYCLIC void test(void)
{
VA_Line(1,VC_HANDLE, 10, 10, 100, 100, 1);
}
This is incorrect! VA_Saccess hasn't been called here.
Introduction to Visual Components 2.3
158 3.3.8.22 Requirements and Initialization − VA_Saccess