test GDALAutoCreateWarpedVRT

autowarp_test.c

#include <cpl_conv.h>
#include <ogr_srs_api.h>
#include <gdalwarper.h>

/*
* https://www.gdal.org/warptut.html
*/
int main()
{
    GDALAllRegister();

    // Open input and output files.
    GDALDatasetH hSrcDS = GDALOpenShared( "cq-dem.tif", GA_ReadOnly );

    OGRSpatialReferenceH dstSRS = OSRNewSpatialReference(NULL);
    OSRImportFromEPSG(dstSRS, 3857);
    char *pszDstWKT = NULL;
    OSRExportToWkt(dstSRS, &pszDstWKT);
    OSRDestroySpatialReference(dstSRS);
    printf("pass...\r\n%s\r\n", pszDstWKT);

    GDALDatasetH hDstDS = GDALAutoCreateWarpedVRT(hSrcDS,
            GDALGetProjectionRef(hSrcDS), pszDstWKT,
            GRA_NearestNeighbour,
            0.0,
            NULL);

    // save as xml file, just for edit the VRT as a xml file, 
    GDALDriverH hDriver = GDALGetDatasetDriver(hDstDS);
    GDALDatasetH hOutDS = GDALCreateCopy(hDriver, "my-dem.vrt", hDstDS, 
                                         FALSE, NULL, NULL, NULL);
    GDALClose(hOutDS);

    // do the work with hDstDS, as the warp VRT dataset, 
    // ...
    
    CPLFree(pszDstWKT);
    GDALClose( hDstDS );
    GDALClose( hSrcDS );

    return 0;
}

gcc gdal-config --cflags warp_test.c gdal-config --libs