va_arg()
Retrieve the next argument in a function's variable argument list
Syntax
va_arg(va-list)
Parameter
Parameter | Definition |
|---|---|
va-list | PSL list containing a variable number of arguments |
Description
Th e va_arg() function returns the next argument from the variable-length list va-list. If there are no mo re arguments in va-list, t he va_arg() function returns the NULL string and sets the PSL variable errno = 69 (E_PSL_ERANGE).
When used with the va_start() function, the va_arg() can read a variable argument list multiple times, using the va_start() function to reset the list after each reading. (The va_start() function always resets the variable argument list to return the first argument.)
Example
The following is an exam ple of the va_arg() functio n:
function summation(...) {
c = sum = 0;
terms = va_start();
c = va_arg(terms);
while (c != "") {
sum += c;
c = va_arg(terms);
}
return sum;
}
function main() {
print("Sum of the first 2 numbers is : ",summation(1,2),"\n");
print("Sum of the first 3 numbers is : ",summation(1,2,3),"\n");
print("Sum of the first 4 numbers is : ",summation(1,2,3,4),"\n");
print("Sum of the first 5 numbers is : ",summation(1,2,3,4,5),"\n");
print("Sum of the first 6 numbers is : ",summation(1,2,3,4,5,6),"\n");
print("Sum of the first 7 numbers is : ",summation(1,2,3,4,5,6,7),"\n");
print("Sum of the first 8 numbers is : ",summation(1,2,3,4,5,6,7,8),"\n");
print("Sum of the first 9 numbers is : ",summation(1,2,3,4,5,6,7,8,9),"\n");
return;
}
c = sum = 0;
terms = va_start();
c = va_arg(terms);
while (c != "") {
sum += c;
c = va_arg(terms);
}
return sum;
}
function main() {
print("Sum of the first 2 numbers is : ",summation(1,2),"\n");
print("Sum of the first 3 numbers is : ",summation(1,2,3),"\n");
print("Sum of the first 4 numbers is : ",summation(1,2,3,4),"\n");
print("Sum of the first 5 numbers is : ",summation(1,2,3,4,5),"\n");
print("Sum of the first 6 numbers is : ",summation(1,2,3,4,5,6),"\n");
print("Sum of the first 7 numbers is : ",summation(1,2,3,4,5,6,7),"\n");
print("Sum of the first 8 numbers is : ",summation(1,2,3,4,5,6,7,8),"\n");
print("Sum of the first 9 numbers is : ",summation(1,2,3,4,5,6,7,8,9),"\n");
return;
}
The example produces the following output:
Sum of the first 2 numbers is : 3.000000
Sum of the first 3 numbers is : 6.000000
Sum of the first 4 numbers is : 10.000000
Sum of the first 5 numbers is : 15.000000
Sum of the first 6 numbers is : 21.000000
Sum of the first 7 numbers is : 28.000000
Sum of the first 8 numbers is : 36.000000
Sum of the first 9 numbers is : 45.000000
Sum of the first 3 numbers is : 6.000000
Sum of the first 4 numbers is : 10.000000
Sum of the first 5 numbers is : 15.000000
Sum of the first 6 numbers is : 21.000000
Sum of the first 7 numbers is : 28.000000
Sum of the first 8 numbers is : 36.000000
Sum of the first 9 numbers is : 45.000000
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