How to Decompress jpeg Images Using libjpeg

This is a function I wrote to decompress jpeg images using libjpeg:

#include <jpeglib.h>

int decode_frame(const char *buffer, int length, void *samples)
{
    int n_samples;
    struct jpeg_error_mgr err;
    struct jpeg_decompress_struct cinfo = {0};

    /* create decompressor */
    jpeg_create_decompress(&cinfo);
    cinfo.err = jpeg_std_error(&err);
    cinfo.do_fancy_upsampling = FALSE;

    /* set source buffer */
    jpeg_mem_src(&cinfo, buffer, length);

    /* read jpeg header */
    jpeg_read_header(&cinfo, 1);

    /* decompress */
    jpeg_start_decompress(&cinfo);

    /* read scanlines */
    while (cinfo.output_scanline < cinfo.output_height) {
        n_samples = jpeg_read_scanlines(&cinfo, (JSAMPARRAY) &samples, 1);
        samples += n_samples * cinfo.image_width * cinfo.num_components;
    }   

    /* clean up */
    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);
    return 0;
}