Global Variables functions

kokas · 10-23-2006, 02:37 PM

Global Variables functions

bool GlobalVariableCheck(
string name)

Return logical true if global variable exists, otherwise returns false. To get the detailed error information, call GetLastError() function.

Parameters

name
-
Global variable name.

Sample
// check variable before use
if(!GlobalVariableCheck("g1"))
GlobalVariableSet("g1",1);

bool GlobalVariableDel(
string name)

Deletes global variable. If the function succeeds, the return value will be true. If the function fails, the return value is false. To get the detailed error information, call GetLastError().

Parameters

name
-
Global variable name.

Sample
// deleting global variable with name "gvar_1"
GlobalVariableDel("gvar_1");

double GlobalVariableGet(
string name)

Returns global variable value. To check function failure, check error information by calling GetLastError().

Parameters

name
-
Global variable name.

Sample
double v1=GlobalVariableGet("g1");
//---- check function call result
if(GetLastError()!=0) return(false);
//---- continue processing

datetime GlobalVariableSet(
string name, double value)

Sets global variable value. If it does not exist, the system creates a new variable. If the function succeeds, the return value is last access time. If the function fails, the return value is 0. To get the detailed error information, call GetLastError().

Parameters

name
-
Global variable name.
value
-
Numeric value to set.

Sample
//---- try to set new value
if(GlobalVariableSet("BarsTotal",Bars)==0)
return(false);
//---- continue processing

bool GlobalVariableSetOnCondition(
string name, double value, double check_value)

Sets the new value of the global variable if the current value equals to the third parameter check_value. If there is no variable at all, the function will return false and set the value of ERR_GLOBAL_VARIABLE_NOT_FOUND constant to LastError. When successfully executed, the function returns true, otherwise it does false. To receive the information about the error, call GetLastError() function.
The function can be used as a semaphore for the access to common resources.

Parameters

name
-
Global variable name.
value
-
Numeric value to set.
check_value
-
Value to compare with the current global variable value.

Sample
int init()
{
//---- create global variable
GlobalVariableSet("DATAFILE_SEM",0);
//...
}

int start()
{
//---- try to lock common resource
while(!IsStopped())
{
//---- locking
if(GlobalVariableSetOnCondition("DATAFILE_SEM",1,0 )==true) break;
//---- may be variable deleted?
if(GetLastError()==ERR_GLOBAL_VARIABLE_NOT_FOUND) return(0);
//---- sleeping
Sleep(500);
}
//---- resource locked
// ... do some work
//---- unlock resource
GlobalVariableSet("DATAFILE_SEM",0);
}

void GlobalVariablesDeleteAll(
)

Deletes all global variables. This function never fails.

Sample
GlobalVariablesDeleteAll();