CreateDC function

Creates a device context (DC) for a device using the specified driver.

Syntax

Parameters

Return Value

Remarks

Example

HDC CreateDC(
    LPCTSTR   pwszDriver,
    LPCTSTR   pwszDevice,
    LPCTSTR   pwszOutput,
    const DEVMODE *pdevmode
);

Parameter	Type	Description
pwszDriver	LPCTSTR	Name of the device driver (e.g., "DISPLAY").
pwszDevice	LPCTSTR	Device name; can be `NULL` for the default device.
pwszOutput	LPCTSTR	Port name (e.g., "COM1:"); can be `NULL`.
pdevmode	const DEVMODE*	Pointer to a `DEVMODE` structure that defines the device initialization parameters; can be `NULL` for defaults.

Returns a handle to the newly created device context. If the function fails, the return value is NULL. Call GetLastError for extended error information.

The created DC can be used with any GDI functions that accept an HDC.
When you are finished with the DC, release it with DeleteDC.
For printer devices, specify the printer driver name and device name obtained from EnumPrinters.
Passing NULL for pwszDriver and pwszDevice creates a screen DC for the primary monitor.

#include <windows.h>
#include <stdio.h>

int main() {
    HDC hdc = CreateDC(L"DISPLAY", NULL, NULL, NULL);
    if (!hdc) {
        printf("CreateDC failed: %ld\n", GetLastError());
        return 1;
    }

    // Draw a simple rectangle
    RECT rc = {50, 50, 300, 200};
    FillRect(hdc, &rc, (HBRUSH)(COLOR_WINDOW+1));

    // Clean up
    DeleteDC(hdc);
    return 0;
}