VXi VT1529A/B 사용자 설명서

Global variables are those declared outside of both the main() function and 
any algorithms (see Figure 6-1). A global variable can be read or changed by 
any algorithm. To declare global variables, use the command:

ALG:DEF 'GLOBALS','<source_code>'

where <source_code> is Algorithm Language source limited to constructs 
for declaring variables. It must not contain executable statements. 
Examples:

ALG:DEF 'GLOBALS','static float glob_scal_var;'

ALG:DEF 'GLOBALS','static float glob_scal_var = 22.53;'

ALG:DEF 'GLOBALS','static float glob_scal_var, glob_array_var[12];'

Global variables are accessed within an algorithm like any other variable.

glob_scal_var = P_factor * I108

1. All variables must be declared static float.
2. Array variables cannot be assigned a value when declared.
3. All variables declared within an algorithm are local to that algorithm. 

If a variable with the same identifier as an existing global variable is 
locally declared, the algorithm will access the local variable only.

The VT1422A always declares the global variable first_loop. First_loop is 
set to 1 each time INIT is executed. After main() calls all enabled algorithms, 
it sets First_loop to 0. By testing First_loop, an algorithm can determine if 
it is being called for the first time since an INITiate command was received. 
Example:

static float scalar_var;
static float array_var [ 4 ];

/* assign constants to variables on first pass only */
if ( First_loop )
{

scalar_var = 22.3;
array_var[0] = 0;
array_var[1] = 0;
array_var[2] = 1.2;
array_var[3] = 4;

}