Yalantis/uCrop · error · CImgArgumentException

load_magick(): Specified filename is (null).

Error message

load_magick(): Specified filename is (null).

What it means

load_magick() validates its filename argument first: a NULL pointer cannot name any file, so CImg throws CImgArgumentException immediately. This is a caller programming error caught by defensive argument checking, thrown regardless of whether libMagick++ is enabled.

Source

Thrown at ucrop/src/main/jni/CImg.h:57266

            if (ptr_a) *(ptr_a++) = (T)*(ptrs++);
          }
        }
      } break;
      }
      JxlDecoderDestroy(decoder);
      return *this;
#endif
    }

    //! Load image from a file, using Magick++ library.
    /**
       \param filename Filename, as a C-string.
    **/
    // Added April/may 2006 by Christoph Hormann <chris_hormann@gmx.de>.
    // This is experimental code, not much tested, use with care.
    CImg<T>& load_magick(const char *const filename) {
      if (!filename)
        throw CImgArgumentException(_cimg_instance
                                    "load_magick(): Specified filename is (null).",
                                    cimg_instance);

#ifdef cimg_use_magick
      Magick::Image image(filename);
      const unsigned int W = image.size().width(), H = image.size().height();
      switch (image.type()) {
      case Magick::PaletteMatteType :
      case Magick::TrueColorMatteType :
      case Magick::ColorSeparationType : {
        assign(W,H,1,4);
        T *ptr_r = data(0,0,0,0), *ptr_g = data(0,0,0,1), *ptr_b = data(0,0,0,2), *ptr_a = data(0,0,0,3);
        Magick::PixelPacket *pixels = image.getPixels(0,0,W,H);
        for (ulongT off = (ulongT)W*H; off; --off) {
          *(ptr_r++) = (T)(pixels->red);
          *(ptr_g++) = (T)(pixels->green);
          *(ptr_b++) = (T)(pixels->blue);
          *(ptr_a++) = (T)(pixels->opacity);

View on GitHub (pinned to f788b534b4)

Solutions

1. Ensure a non-NULL filename string is passed; check the source of the path before calling.
2. Provide a default path when the lookup can fail (e.g. getenv fallback).
3. Switch to std::string-based handling so empty/absent paths are caught before the C-string boundary.

Example fix

// before
const char* p = getenv("IMG_PATH");
img.load_magick(p); // NULL if unset
// after
const char* p = getenv("IMG_PATH");
if (p) img.load_magick(p); else img.load_magick("/default/img.png");

bool validPath(const char* p) { return p != nullptr && p[0] != '\0'; }

try { img.load_magick(path); } catch (CImgArgumentException& e) { log("null filename passed to load_magick"); }

When it happens

Trigger: Calling CImg<T>::load_magick(NULL), or passing the result of a lookup function that returned NULL (e.g. getenv of an unset var, failed path resolution).

Common situations: Path taken from a missing environment variable or failed string conversion; uninitialized char* members; C APIs returning NULL for 'not found' passed straight through.

Related errors

• load_jpeg(): Specified filename is (null).
• load_jxl(): Specified filename is (null).
• load_pfm(): Specified filename is (null).
• load_rgb(): Specified filename is (null).
• load_rgba(): Specified filename is (null).

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/edda7c414e4d5b4a. Report an issue: GitHub.