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WinHttpAddRequestHeadersEx function (winhttp.h)

  • Article

Adds one or more HTTP request headers to an HTTP request handle, allowing you to use separate name/value strings.

Syntax

WINHTTPAPI DWORD WinHttpAddRequestHeadersEx(
  HINTERNET               hRequest,
  DWORD                   dwModifiers,
  ULONGLONG               ullFlags,
  ULONGLONG               ullExtra,
  DWORD                   cHeaders,
  WINHTTP_EXTENDED_HEADER *pHeaders
);

Parameters

hRequest

Type: IN HINTERNET

An HINTERNET handle returned by a call to WinHttpOpenRequest.

dwModifiers

Type: IN DWORD

An unsigned long integer value that contains the flags used to modify the semantics of this function. Can be one or more of the following flags.

Value Meaning
WINHTTP_ADDREQ_FLAG_ADD
 Adds the header if it does not exist. Used with WINHTTP_ADDREQ_FLAG_REPLACE.
WINHTTP_ADDREQ_FLAG_ADD_IF_NEW
 Adds the header only if it does not already exist; otherwise, an error is returned.
WINHTTP_ADDREQ_FLAG_COALESCE
 Merges headers of the same name.
WINHTTP_ADDREQ_FLAG_COALESCE_WITH_COMMA
 Merges headers of the same name using a comma. For example, adding "Accept: text/*" followed by "Accept: audio/*" with this flag results in a single header "Accept: text/*, audio/*". This causes the first header found to be merged. The calling application must to ensure a cohesive scheme with respect to merged and separate headers.
WINHTTP_ADDREQ_FLAG_COALESCE_WITH_SEMICOLON
 Merges headers of the same name using a semicolon.
WINHTTP_ADDREQ_FLAG_REPLACE
 Replaces or removes a header. If the header value is empty and the header is found, it is removed. If the value is not empty, it is replaced.

ullFlags

Type: IN ULONGLONG

Pass WINHTTP_EXTENDED_HEADER_FLAG_UNICODE to indicate that the strings passed in are Unicode strings.

ullExtra

Type: IN ULONGLONG

Reserved.

cHeaders

Type: IN DWORD

The number of elements in pHeaders.

pHeaders

Type: _In_reads_(cHeaders) WINHTTP_EXTENDED_HEADER*

An array of WINHTTP_EXTENDED_HEADER structures.

Return value

A status code indicating the result of the operation. Among the error codes returned are the following.

Error Code Description
ERROR_WINHTTP_INCORRECT_HANDLE_STATE
 The requested operation cannot be performed because the handle supplied is not in the correct state.
ERROR_WINHTTP_INCORRECT_HANDLE_TYPE
 The type of handle supplied is incorrect for this operation.
ERROR_WINHTTP_INTERNAL_ERROR
 An internal error has occurred.
ERROR_NOT_ENOUGH_MEMORY
 Not enough memory was available to complete the requested operation.

Requirements

Requirement Value
Minimum supported client Windows 10 Build 20348
Minimum supported server Windows 10 Build 20348
Target Platform Windows
Header winhttp.h
Library Winhttp.lib
DLL Winhttp.dll

See also