Yalantis/uCrop · error · CImgArgumentException

save_pfm(): Specified filename is (null).

Error message

save_pfm(): Specified filename is (null).

What it means

Raised by _save_pfm()'s argument-validation guard when both the output FILE* and the filename are null, so the library has nowhere to write the PFM data (the '(null)' text is its way of printing the missing filename). This is a generic sentinel error, not a filesystem failure; pass either an open file handle or a destination filename.

Solutions

1. Provide a valid filename to save_pfm()
2. Open a FILE* yourself and pass it to the FILE* overload
3. Guard the call site: only call save_pfm when a destination exists

Example fix

// before
if (saveHdr) img.save_pfm(hdrPath.empty() ? NULL : hdrPath.c_str());
// after
if (saveHdr && !hdrPath.empty()) img.save_pfm(hdrPath.c_str());

if (!file && (!filename || !*filename)) throw std::invalid_argument("save_pfm requires a filename or FILE*");

bool hasDestination(std::FILE *f, const char *name) { return f != NULL || (name != NULL && name[0] != '\0'); }

try { img.save_pfm(path.c_str()); } catch (CImgArgumentException &e) { /* handle */ }

When it happens

Trigger: Calling save_pfm((std::FILE*)0) or _save_pfm(file,0) with a null file; forwarding a null filename through generic save-dispatch code.

Common situations: HDR pipeline where the PFM output path is optional but save_pfm is still invoked; fopen failure unchecked; null path from CLI/config defaults.

Related errors

• save_pnk(): Specified filename is (null).
• save_pnm(): Specified filename is (null).
• save_rgb(): Specified filename is (null).
• save_rgba(): Specified filename is (null).
• load_cimg(): Specified filename is (null).

AI-assisted analysis of Yalantis/uCrop@f788b534b4 (2026-09-08). Data as JSON: /api/errors/4ea1c7a287979dc9. Report an issue: GitHub.

Appendix: source

Thrown at ucrop/src/main/jni/CImg.h:62481

    //! Save image as a PFM file.
    /**
      \param filename Filename, as a C-string.
    **/
    const CImg<T>& save_pfm(const char *const filename) const {
      get_mirror('y')._save_pfm(0,filename);
      return *this;
    }

    //! Save image as a PFM file \overloading.
    const CImg<T>& save_pfm(std::FILE *const file) const {
      get_mirror('y')._save_pfm(file,0);
      return *this;
    }

    const CImg<T>& _save_pfm(std::FILE *const file, const char *const filename) const {
      if (!file && !filename)
        throw CImgArgumentException(_cimg_instance
                                    "save_pfm(): Specified filename is (null).",
                                    cimg_instance);
      if (is_empty()) { cimg::fempty(file,filename); return *this; }
      if (_depth>1)
        cimg::warn(_cimg_instance
                   "save_pfm(): Instance is volumetric, only the first slice will be saved in file '%s'.",
                   cimg_instance,
                   filename?filename:"(FILE*)");
      if (_spectrum>3)
        cimg::warn(_cimg_instance
                   "save_pfm(): image instance is multispectral, only the three first channels will be saved "
                   "in file '%s'.",
                   cimg_instance,
                   filename?filename:"(FILE*)");

      std::FILE *const nfile = file?file:cimg::fopen(filename,"wb");
      const T
        *ptr_r = data(0,0,0,0),

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