Yalantis/uCrop · error · CImgArgumentException

load_dlm(): Specified filename is (null).

Error message

load_dlm(): Specified filename is (null).

What it means

CImg<T>::load_dlm() needs either an open std::FILE* or a non-null filename; both being null throws CImgArgumentException immediately. DLM is the delimiter-separated values loader, and there is nothing to parse without a source.

Source

Thrown at ucrop/src/main/jni/CImg.h:56716

    //! Load image from a DLM file \newinstance.
    static CImg<T> get_load_dlm(const char *const filename) {
      return CImg<T>().load_dlm(filename);
    }

    //! Load image from a DLM file \overloading.
    CImg<T>& load_dlm(std::FILE *const file) {
      return _load_dlm(file,0);
    }

    //! Load image from a DLM file \newinstance.
    static CImg<T> get_load_dlm(std::FILE *const file) {
      return CImg<T>().load_dlm(file);
    }

    CImg<T>& _load_dlm(std::FILE *const file, const char *const filename) {
      if (!file && !filename)
        throw CImgArgumentException(_cimg_instance
                                    "load_dlm(): Specified filename is (null).",
                                    cimg_instance);

      std::FILE *const nfile = file?file:cimg::fopen(filename,"r");
      CImg<charT> delimiter(256), tmp(256); *delimiter = *tmp = 0;
      unsigned int cdx = 0, dx = 0, dy = 0;
      int err = 0;
      double val;
      assign(256,256,1,1,(T)0);
      while ((err = std::fscanf(nfile,"%lf%255[^0-9eEinfa.+-]",&val,delimiter._data))>0) {
        if (err>0) (*this)(cdx++,dy) = (T)val;
        if (cdx>=_width) resize(3*_width/2,_height,1,1,0);
        char c = 0;
        if (!cimg_sscanf(delimiter,"%255[^\n]%c",tmp._data,&c) || c=='\n') {
          dx = std::max(cdx,dx);
          if (++dy>=_height) resize(_width,3*_height/2,1,1,0);
          cdx = 0;
        }

View on GitHub (pinned to f788b534b4)

Solutions

1. Supply a valid filename or FILE* to load_dlm.
2. Guard the call site with a null check on the path.
3. If the data is in memory, parse it yourself or convert to a file/stream first.

Example fix

// before
img.load_dlm(path, sep); // path==nullptr
// after
assert(path != nullptr);
img.load_dlm(path, sep);

if (!path) throw std::invalid_argument("load_dlm requires a filename");

bool hasDlmSource(std::FILE* f, const char* name){ return f != nullptr || name != nullptr; }

try { img.load_dlm(path, delim); } catch (cimg_library::CImgArgumentException& e) { /* null source */ }

When it happens

Trigger: Calling load_dlm(nullptr) or the dispatch overload where both file and filename are NULL, typically from an unset path variable.

Common situations: Forwarding an optional config path that was never configured; calling the static get_load_dlm wrappers indirectly with default null arguments.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• load_dlm(): Invalid DLM file '%s'.
• load(): Specified filename is (null).
• load_ascii(): Specified filename is (null).
• load_bmp(): Specified filename is (null).
• load_jpeg(): Specified filename is (null).

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/81a7e2b4adf581d7. Report an issue: GitHub.