Delete 128 bytes of a file. | Together C & C++ | Page 1

tepid wigeonBOT Dec 19, 2025, 4:00 AM

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plucky osprey Dec 19, 2025, 6:48 AM

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I have the following solution in mind:

fopen the file in read mode

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copy the contents to a buffer
reopen the file in write mode (destroys the contents)
write it back (excluding your 128 bytes)

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https://en.cppreference.com/w/c/io/fopen.html

floral parcel Dec 19, 2025, 9:14 AM

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and if the process dies for whatever reason - bye, bye file

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a popular method is to write to a new file, then rename the new to old, overwriting the old one, but rename() doesn't have the greatest guarantees in C per se

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this is the life in C, the standard library is tiny, and lacks many things, so either you #ifdef your way through multiple platforms or you use 3rd party libraries, that do

floral parcel Dec 19, 2025, 9:28 AM

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floral parcel a popular method is to write to a new file, then rename the new to old, overwrit...

(the guarantees are present, but in POSIX rename())

tepid wigeonBOT Dec 21, 2025, 10:02 AM

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tepid wigeonBOT Dec 28, 2025, 3:10 PM

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#Delete 128 bytes of a file.