RE: [fltk.general] Re: Does Fl_Image always release the lock on the fileit is reading - Forums

From: lifeatt...@gmail.com
Sent: 27 July 2022 15:07
To: fltk.general
Subject: [fltk.general] Re: Does Fl_Image always release the lock on the fileit is reading

Fl_Image doesn't have any link to the file or other resources. Fl_PNG_Image does an fopen() and a fclose().

So the following sequence (FLTK 1.4, Linux, installed PNG library) works:

Fl_Image *img;
Fl_Image *imgc;

img = new Fl_PNG_Image("folder.png");
imgc = img->copy(250, 250);
delete img;

FILE *imgF = fopen("folder.png", "wb");
fputc(0, imgF);
fclose(imgF);

The file which was opened by Fl_PNG_Image is successfully clobbered by the subsequent fopen/fputc.

I have noticed that I am not allowed to update a file after I've opened it with Fl_PNG_Image.

Thanks,

I didn’t think it would be a problem. I’ll need to look elsewhere if it happens again.

I am running on W10 using the libraries from fltk. FLTK 1.4.

Phil.