header-w32api_h

The following values have been copied from the w32api.h that comes with w32api-3.7:

/* Use these values to set _WIN32_WINDOWS and WINVER to your minimum support
 * level */
#define Windows95    0x0400
#define Windows98    0x0410
#define WindowsME    0x0500

/* Use these values to set _WIN32_WINNT and WINVER to your mimimum support
 * level. */
#define WindowsNT4   0x0400
#define Windows2000  0x0500
#define WindowsXP    0x0501
#define Windows2003  0x0502
#define WindowsVista 0x0600

/* Use these values to set _WIN32_IE to your minimum support level */
#define IE3     0x0300
#define IE301   0x0300
#define IE302   0x0300
#define IE4     0x0400
#define IE401   0x0401
#define IE5     0x0500
#define IE5a    0x0500
#define IE5b    0x0500
#define IE501   0x0501
#define IE55    0x0501
#define IE56    0x0560
#define IE6     0x0600
#define IE601   0x0601
#define IE602   0x0603
#define IE7     0x0700

Define WINVER to the minimum required value your program needs at the top of your code but beware that if you e.g. give

#include <winapi.h>
#define WINVER WindowsXP

or if you didn't include anything before

#define WINVER 0x0501

your program probably won't even start on W2K or WinNT.

A similar statement goes for defining _WIN32_IE.

Note that you should not set _WIN32_WINNT directly unless you know what you are doing because _WIN32_WINNT is defined to WINVER if not explicitly set anyway.