Yalantis/uCrop · error · CImgArgumentException

load_pdf_external(): Specified filename is (null).

Error message

load_pdf_external(): Specified filename is (null).

What it means

load_pdf_external() renders a PDF page via external ghostscript ('gs'). It first validates its argument: if filename is null it throws this CImgArgumentException. Unlike some sibling loaders it only checks for null, not for file existence.

Source

Thrown at ucrop/src/main/jni/CImg.h:59907

      cimg::split_filename(command,body);
      cimg_snprintf(command,command._width,"%s.img",body._data);
      std::remove(command);
      return *this;
    }

    //! Load image from a DICOM file, using Medcon's external tool 'medcon' \newinstance.
    static CImg<T> get_load_medcon_external(const char *const filename) {
      return CImg<T>().load_medcon_external(filename);
    }

    //! Load image from a .pdf file.
    /**
       \param filename Filename, as a C-string.
       \param resolution Image resolution.
    **/
    CImg<T>& load_pdf_external(const char *const filename, const unsigned int resolution=400) {
      if (!filename)
        throw CImgArgumentException(_cimg_instance
                                    "load_pdf_external(): Specified filename is (null).",
                                    cimg_instance);
      CImg<charT> command(1024), filename_tmp(256);
      const CImg<charT> s_filename = CImg<charT>::string(filename)._system_strescape();
#if cimg_OS==1
      std::FILE *file = 0;
      cimg_snprintf(command,command._width,"gs -q -dNOPAUSE -sDEVICE=ppmraw -o - -r%u \"%s\"",
                    resolution,s_filename.data());
      file = popen(command,"r");
      if (file) {
        const unsigned int omode = cimg::exception_mode();
        cimg::exception_mode(0);
        try { load_pnm(file); } catch (...) {
          pclose(file);
          cimg::exception_mode(omode);
          throw CImgIOException(_cimg_instance
                                "load_pdf_external(): Failed to load file '%s' with external command 'gs'.",
                                cimg_instance,

View on GitHub (pinned to f788b534b4)

Solutions

1. Null-check the filename (or assert it) before calling load_pdf_external.
2. Resolve the source of the null path (config key, env var, DB field) and provide a default or explicit failure earlier.
3. Also verify the file exists yourself, since this function does not check existence: cimg::is_file(path).
4. Refuse to proceed with a clear application-level error instead of passing null into the loader.

Example fix

// before
img.load_pdf_external(path); // path may be NULL
// after
if (!path) throw std::invalid_argument("PDF path is null");
if (!cimg::is_file(path)) throw std::invalid_argument("PDF not found");
img.load_pdf_external(path);

if (!path) throw std::invalid_argument("PDF path is null");
if (!cimg::is_file(path)) throw std::invalid_argument("PDF file not found");

bool validPdfPath(const char* p){ return p && cimg::is_file(p); }

try { img.load_pdf_external(path, res); }
catch (CImgArgumentException& e) { log("null/invalid PDF path"); }

When it happens

Trigger: Calling CImg<T>::load_pdf_external(nullptr) or load_pdf_external(NULL, resolution); typically when a path variable was never assigned, an optional config value is absent, or an upstream API returned null for the document path.

Common situations: Null returned by getenv()/config lookup passed straight through; caller of a wrapper function forwarding an unset filename; strings from JSON deserialization where the key was missing.

Related errors

• load_pdf_external(): Failed to load file '%s' with external
• load(): Specified filename is (null).
• load_ascii(): Specified filename is (null).
• load_dlm(): Specified filename is (null).
• load_bmp(): Specified filename is (null).

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/df0f8247351ff2e2. Report an issue: GitHub.