HttpSendRequest

Opens the connection to the destination and sends the request.

Syntax

    #include <httpexp.h>
    #include <httpclnt.h> 
     
    int HttpSendRequest (
       HINTERNET   hndl,
       void       *pDataBuffer,
       UINT32      dataBufferLen,
       void       *pContext,
       void      (*pCallBackRoutine)(
                  void       *pContext,
                  HINTERNET   hndl,
                  int         returnCode,
                  void       *reserved)
       );

Parameters

hndl
(IN) Specifies the connection handle returned from HttpConnect.
pDataBuffer
(IN) Points to optional data for the body of the request.
dataBufferLen
(IN) Specifies the length of the data pointed to by the pDataBuffer parameter.
pContext
(IN) Points to optional context data, which is passed to your callback function. For a synchronous request, set it to NULL.
pCallBackRoutine
(IN) Points to the callback function that is called when an asynchronous request returns. For a synchronous request, set it to NULL.

The callback function is passed the following parameters:

  • pContext—Points to any optional context data that you passed in when you called HttpSendRequest.
  • hndl—Specifies the HTTP connection handle received for this request.
  • returnCode—Specifies the error status for the HttpSendRequest call. Zero indicates no errors; nonzero indicates an error. See Return Values for possible errors.
  • reserved—Reserved for future use. Currently returns NULL.

Return Values

If successful, returns 0. For an asynchronous request, success means that the parameters are valid and the request has been sent. For a synchronous request, success means that the request has been sent and the reply has been received.

On failure, returns a nonzero error code.

Decimal

Name

Description

168

ERR_ACCESS_DENIED

The handle is invalid, the call was made out of sequence, or the call was made when a callback on the handle is pending.

255

ERR_BAD_PARAMETER

An invalid parameter was passed to the function.

>10000

WSA...

WinSock errors.

Remarks

Once a request has been built, you use the HttpSendRequest function to open the connection at the destination and send the request. You can supply the data portion of the request, in full or in part, with this function.

The HttpSendRequest function can be used synchronously or asynchronously. In synchronous mode, the function blocks until the send is completed and the status is returned. To use this mode, set the pContext and pCallBackRoutine parameters to NULL.

In asynchronous mode, the initial status returns immediately. If it is zero, the request has been accepted and your callback function is called when the reply is received and parsed. If the initial status is nonzero, an error has occurred, the request is not sent, and your callback function is never called.

See Also