Syntax

  #include <stdarg.h> 
    
  type va_arg  (  
     va_list param,   
     type);
  

Parameters

param

(IN) Specifies a variable argument.

type

(IN) Specifies the argument type.

Return Values

va_arg returns the value of the next variable argument, according to type passed as the second parameter.

Remarks

The macro va_arg can be used to obtain the next argument in a list of variable arguments. It must be used with the associated macros va_start and va_end. A sequence such as:

     va_list curr_arg;  
     type next_arg; 
     next_arg = va_arg (curr_arg, type);
  

causes next_arg to be assigned the value of the next variable argument. The type is the type of the argument originally passed.

The macro va_start must be executed first in order to properly initialize the variable next_arg and the macro va_end should be executed after all arguments have been obtained.

The data item curr_arg is of type va_list which contains the information to permit successive acquisitions of the arguments.

See Also

va_end, va_start, vfprintf, vprintf (Single and Intra-File Management), vsprintf

Example

  #include <stdarg.h>  
   
  void test_fn (const char *msg, const char *types,  ...); 
    
  int main ()  
  {  
        printf ("VA...TEST\n");  
        test_fn ("PARAMETERS: 1, \"abc\", 546", "isi", 1, "abc", 546 );  
        test_fn ("PARAMETERS: \"def\", 789", "si", "def", 789 );  
  }  
   
  static void test_fn (  
   
  const char *msg,      /* Message to be printed */  
  const char *types,    /* Parameter types (i,s) */  
     ... )              /* Variable arguments    */  
   
  {  
     va_list  argument;  
     int   arg_int;  
     char  *arg_string;  
     char *types_ptr;  
     types_ptr = types;  
     printf ("\n%s - %s\n", msg, types);  
     va_start (argument, types);  
     while (*types_ptr != `\0’)  
     {  
        if (*types_ptr == `i’)  
        {  
           arg_int = va_arg (argument, int );  
           printf  ("integer: %d\n", arg_int );  
        }  
        else if (*types_ptr == `s’)  
        {  
           arg_string = va_arg ( argument, char *);  
           printf ("string:  %s\n", arg_string);  
        }  
        ++types_ptr;  
     }  
     va_end (argument);  
  }
  

produces the following:

  PARAMETERS: 1, "abc", 546  
  integer: 1  
  string:  abc  
  integer: 546  
  PARAMETERS: "def", 789  
  string:  def  
  integer: 789