TipcMsgReadVa

Name

TipcMsgReadVa — read fields from a message (va_list version)

Synopsis

T_BOOL TipcMsgReadVa(msg, var_arg_list) 
T_IPC_MSG msg; 
va_list var_arg_list;

Arguments

msg — message to read fields from

var_arg_list — argument list

Return Values

TRUE if all the fields were successfully read, FALSE otherwise.

Diagnostics

If TipcMsgReadVa fails, it returns FALSE and sets the global SmartSockets error number to one of:

T_ERR_NULL_PTR — msg was null

T_ERR_MSG_INVALID — msg was not a valid message

T_ERR_FT_INVALID — a field type argument was not a valid field type

T_ERR_MSG_EOM — the current field is at the end of message

T_ERR_VAL_UNKNOWN — the current field is of value unknown

any error number from TipcMsgNext*

Description

TipcMsgReadVa is the non-varargs version of TipcMsgRead. (TipcMsgRead actually calls TipcMsgReadVa.) TipcMsgReadVa can be used to implement a varargs function.

In the C language, a varargs function (one that takes a variable number of arguments) cannot call another varargs function with the original arguments. A varargs function can (and usually does) call a helper function that takes a fixed number of arguments, with the last argument usually of type va_list. TipcMsgReadVa is TipcMsgRead’s helper function.

Caution

None

Examples

This example shows how to write a varargs function in ANSI C that reads fields from a message and then destroys the message:

T_BOOL my_msg_read_destroy(T_IPC_MSG msg, 
                           ...) 
{ 
  va_list var_arg_list; 
  int read_status; 
  int destroy_status; 
 
  va_start(var_arg_list, msg); 
  read_status = TipcMsgReadVa(msg, var_arg_list); 
  va_end(var_arg_list); 
  destroy_status = TipcMsgDestroy(msg); 
 
  /* return FALSE if either status is FALSE */ 
  return read_status && destroy_status; 
} /* my_msg_read_destroy */