Why did fopen fail

It's a global variable. It's been a while, but probably include errno. Otherwise, NULL is returned and errno is set to indicate the error. Please check whether the file exists in the execution path or in your program, check the errno. Make sure you have the file in your working directory.

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Active 1 year, 3 months ago. Viewed 42k times. I have the following code where I am trying to open a text file. Alan Birtles John John 2 2 gold badges 16 16 silver badges 33 33 bronze badges. Walter Roberson on 2 Sep Vote 1. If you were fclose 'ing the file properly, the file ID would not continuing increasing. So some code execution path is failing to fclose the file after use.

I'll have a look into that. So that would mean that the program is opening and reading each file one by one but not closing them. Can this create an issue though?

I'll see if closing each file after opening has any effect on the outcome. Yes, there is a maximum number of files that can be open using fopen. Well you learn something new everyday! Seems to me that's definitely causing the issue! Closing them after processing should solve the issue then. More Answers 1. Steven Lord on 2 Sep I suspect you're opening the files but not closing them. You can check this using:.

This newsgroup thread is from a couple years ago, but I believe you might find it relevant. Ok great thanks for that. Will check it out when I get a chance. See Also. Tags fopen fid iteration guide loop. Start Hunting! An Error Occurred Unable to complete the action because of changes made to the page. Select a Web Site Choose a web site to get translated content where available and see local events and offers. The 'b' indicates binary data as opposed to text ; by default, this will be a sequential file in Media 4 format.

The 'b' indicates binary data. Several additional options can be specified by adding one or more letters to the possibilities listed above. All of the following options are unique to the GCOS-8 version of C and will not be portable to other implementations. The file will be accessed random, no buffer will be allocated for processing SSF records. If you do not specify this option, the default is to open the file for character stream or record processing.