From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/c/variadic%2Fva_start.html | 77 -------------------------------------- 1 file changed, 77 deletions(-) delete mode 100644 devdocs/c/variadic%2Fva_start.html (limited to 'devdocs/c/variadic%2Fva_start.html') diff --git a/devdocs/c/variadic%2Fva_start.html b/devdocs/c/variadic%2Fva_start.html deleted file mode 100644 index 8dd8a365..00000000 --- a/devdocs/c/variadic%2Fva_start.html +++ /dev/null @@ -1,77 +0,0 @@ -

va_start

Defined in header <stdarg.h> 
void va_start( va_list ap, parmN );
 (until C23) 
void va_start( va_list ap, ... );
-		 (since C23)

The va_start macro enables access to the variable arguments following the named argument parmN(until C23).

-

va_start shall be invoked with an instance to a valid va_list object ap before any calls to va_arg.

- - - - -

If parmN is declared with register storage class specifier, with an array type, with a function type, or with a type not compatible with the type that results from default argument promotions, the behavior is undefined.

-		 (until C23)

Only the first argument passed to va_start is evaluated. Any additional arguments are neither expanded nor used in any way.

-		 (since C23)

Parameters

- - -
ap - an instance of the va_list type
parmN - the named parameter preceding the first variable parameter

Expanded value

(none)

-

Example

#include <stdio.h>
-#include <stdarg.h>
- 
-int add_nums_C99(int count, ...)
-{
-    int result = 0;
-    va_list args;
-    va_start(args, count); // count can be omitted since C23
- 
-    for (int i = 0; i < count; ++i) {
-        result += va_arg(args, int);
-    }
- 
-    va_end(args);
-    return result;
-}
- 
-#if __STDC_VERSION__ > 201710L
-// Same as above, valid since C23
-int add_nums_C23(...)
-{
-    int result = 0;
-    va_list args;
-    va_start(args);
- 
-    int count = va_arg(args, int);
-    for (int i = 0; i < count; ++i) {
-        result += va_arg(args, int);
-    }
- 
-    va_end(args);
-    return result;
-}
-#endif
- 
-int main(void)
-{
-    printf("%d\n", add_nums_C99(4, 25, 25, 50, 50));
-#if __STDC_VERSION__ > 201710L
-    printf("%d\n", add_nums_C23(4, 25, 25, 50, 50));
-#endif
-}

Possible output:

-
150
-150

References

See also

- - - - -
accesses the next variadic function argument
(function macro)
-
(C99)
 makes a copy of the variadic function arguments
(function macro)
ends traversal of the variadic function arguments
(function macro)
holds the information needed by va_start, va_arg, va_end, and va_copy
(typedef)
C++ documentation for va_start
-

- © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
- https://en.cppreference.com/w/c/variadic/va_start -

-
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