You will read the wrong bytes in the fields (the uint32 variable will only have one byte). Now, if you want to read the 5 bytes from your binary file using: Is there a possibility to deal with data packing of the compiler in the structure, because due to this structure members are not necessarily continuous in the memory.įor example, the size of a structure with a uint_8 and uint_32 variable in there is usually 8 bytes instead of 5 due to compiler data packing. To open a file in binary mode you must add the letter b to the end of the mode string for example, “wb”.įor the read and write modes, you can add the b, either after the plus sign – “r b” – or before – “rb ”. W – open for reading and writing (overwrite file)Ī – open for reading and writing (append if file exists) R – open for reading and writing, start at beginning W – open for writing (file need not exist)Ī – open for appending (file need not exist) But to keep the syntax correct, we have changed the source code examples. So there will be now difference between the content of a file written with only “w” or “wb”. This is because we write/read records (structs.) But if you open test.bin with text editor, you will see all kinds of ascii values. You are right, if you only look at the syntax. Is this the right declaration of a binary file iso file,Īnd i have no success with fread with iso file. My last message with my binary writer test, is perfect for me, because i can write a hex value directly in file, 00 to FF anywhere i want in file, but i cant read it with fread after, i want practice this with a small file i have create because my true application i want manage. My write is perfect what i want, but i can not read my bin file, i need some help please,įor ( counter=1 counter <= 10 counter ) Hi, after piratical and try to understanding write and read, Or if you want to use int, accept that 4 bytes are written in the binary file (but at least you know now why this is.) If you open the file test.bin with the hex-editor you will only see 1byte (01 in this case) if you compile for intel platform (win32 and linux.) So if you want to see only one byte in your hex editor, change the program to this:įwrite(
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