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Question feed. Stack Overflow works best with JavaScript enabled. Hartley I know this is an older comment, but I am adding this so that someone doesn't read his comment and try to free line in the loop. The memory for line is only allocated once before the loop begins, so it should only be free once after the loop ends.
If you try freeing line inside the loop, you will get unexpected results. Depending on how free treats the pointer. If it just deallocates memory and leaves the pointer pointing at the old location the code may work. If it assigns another value to the pointer then you will overwrite a different section of memory. Do not do this.
To get around you can: Create variable in caller function and pass its address to readLine Allocate memory for line using malloc - in this case line will be persistent Use global variable, although it is generally a bad practice. I found this piece of description in: linux. Raku Escape Raku Escape 3 3 silver badges 3 3 bronze badges.
Also error messages should go to stderr i. This is important since the comparison with EOF will be handled correctly. JeremyP JeremyP Also, you need to tell the function how long the buffer is that you are passing and think of a strategy for handling lines that are too long for the buffer you pass in. Here is my several hours Reading whole file line by line.
Akhil V Suku 1 1 gold badge 10 10 silver badges 33 33 bronze badges. Samir Samir 5, 4 4 gold badges 34 34 silver badges 38 38 bronze badges. Why are you using fgetc instead of fgets? Taner Mansur Taner Mansur 51 2 2 silver badges 5 5 bronze badges.
Implement method to read, and get content from a file input1. Happy coding! Nhat Dinh Nhat Dinh 3, 3 3 gold badges 32 32 silver badges 47 47 bronze badges. After calling you need free in calling context, eg Why are you using the heap malloc instead of the stack? It seems there's a simpler stack based solution with fgets that could be used. Provide a portable and generic getdelim function, test passed via msvc, clang, gcc.
Why do this when fgets exists? Also I do notice don't have a line length limit -- in this case you can use the stack with getline. Both described here: man7.
Show 4 more comments. For brevity, I kept only the first lines of output:. You can see that, this time, we can print full lines of text and not fixed length chunks like in the initial approach.
However, you should be able to test it if you are using Cygwin or Windows Subsystem for Linux. Also, calling getline more than once will overwrite the line buffer, make a copy of the line content if you need to keep it for further processing.
It is interesting to note, that for this particular case the getline function on Linux resizes the line buffer to a max of bytes. If you run the same code on macOS the line buffer is resized to bytes. This is due to the different ways in which getline is implemented on different Unix like systems. As mentioned before, getline is not present in the C standard library.
The fscanf function is part of the C standard library formatted input utilities. Multiple functions are provided for different input sources like scanf to read from stdin , sscanf to read from the character string, and fscanf to read from the FILE pointer stream.
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