WinHTTP Constants

WinHTTP uses the following constants:

Error Messages

Error messages specific to the WinHTTP functions. These functions also return Windows error messages where appropriate. The value that corresponds to each constant is the value of the constant for the application programming interface (API) functions and the lower 16 bits of the error number for the WinHttpRequest object.

HTTP Status Codes

Constants and corresponding values that indicate HTTP status codes returned by servers on the Internet.

Option Flags

Option flags supported by WinHttpQueryOption and WinHttpSetOption. All valid option flags have a value greater than or equal to WINHTTP_FIRST_OPTION and less than or equal to WINHTTP_LAST_OPTION.

INTERNET_PORT

A WORD value indicating the port.

INTERNET_SCHEME

Internet schemes supported by WinHTTP.

Query Info Flags

Attributes and modifiers used by WinHttpQueryHeaders.

WINHTTP_EXTENDED_HEADER_FLAG_UNICODE

Has a value of 0x00000001. Indicates to WinHttpAddRequestHeadersEx that the strings passed in are Unicode strings.

WINHTTP_READ_DATA_EX_FLAG_FILL_BUFFER

Has a value of 0x0000000000000001ull. Instructs WinHttpReadDataEx not to complete the call until the provided data buffer has been filled, or the response is complete. Passing this flag makes the behavior of WinHttpReadDataEx equivalent to that of WinHttpReadData.