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{{title|Variadic functions}}
{{c/variadic/navbar}}

Variadic functions are functions (e.g. {{lc|printf}}) which take a variable number of arguments.

The declaration of a variadic function uses an ellipsis as the last parameter, e.g. {{c|int printf(const char* format, ...);}}. See [[c/language/variadic|variadic arguments]] for additional detail on the syntax and automatic argument conversions.

Accessing the variadic arguments from the function body uses the following library facilities:

{{dsc begin}}
{{dsc h2|Types}}
{{dsc inc|c/variadic/dsc va_list}}

{{dsc h2|Macros}}
{{dsc header|stdarg.h}}
{{dsc inc|c/variadic/dsc va_start}}
{{dsc inc|c/variadic/dsc va_arg}}
{{dsc inc|c/variadic/dsc va_copy}}
{{dsc inc|c/variadic/dsc va_end}}
{{dsc end}}

===Example===
{{example
|Print values of different types.
|code=
#include <stdarg.h>
#include <stdio.h>

void simple_printf(const char* fmt, ...)
{
    va_list args;

    for (va_start(args, fmt); *fmt != '\0'; ++fmt)
    {
        switch(*fmt)
        {
            case 'd':
            {
                int i = va_arg(args, int);
                printf("%d\n", i);
                break;
            }
            case 'c':
            {
                // A 'char' variable will be promoted to 'int'
                // A character literal in C is already 'int' by itself
                int c = va_arg(args, int);
                printf("%c\n", c);
                break;
            }
            case 'f':
            {
                double d = va_arg(args, double);
                printf("%f\n", d);
                break;
            }
            default:
                puts("Unknown formatter!");
                goto END;
        }
    }
END:
    va_end(args);
}

int main(void)
{
    simple_printf("dcff", 3, 'a', 1.969, 42.5);
}
|output=
3
a
1.969000
42.50000
}}

===References===
{{ref std c23}}
{{ref std|section=7.16|title=Variable arguments <stdarg.h>|p=TBD}}
{{ref std end}}
{{ref std c17}}
{{ref std|section=7.16|title=Variable arguments <stdarg.h>|p=TBD}}
{{ref std end}}
{{ref std c11}}
{{ref std|section=7.16|title=Variable arguments <stdarg.h>|p=269-272}}
{{ref std end}}
{{ref std c99}}
{{ref std|section=7.15|title=Variable arguments <stdarg.h>|p=249-252}}
{{ref std end}}
{{ref std c89}}
{{ref std|section=4.8|title=VARIABLE ARGUMENTS <stdarg.h>}}
{{ref std end}}

===See also===
{{dsc begin}}
{{dsc see cpp|cpp/utility/variadic|Variadic functions|nomono=true}}
{{dsc end}}

{{langlinks|ar|cs|de|es|fr|it|ja|ko|pl|pt|ru|tr|zh}}

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