Anything related to C or C++ standard library functions `fgetc` (C) or `std::fgetc` (C++)
A binary-safe file read function in C/C++/PHP that returns the specified number of bytes from a stream
"The fgetc loop variant was consistently 45x slower than the fread loop"
from question ""Optimal" IO Buffering - Programmer's or Kernel's Task?"
"You might have even noticed the fgetc version is simpler than the fread version"
from question "Why is reading blocks of data faster than reading byte by byte in file I/O"
"Doing things like 1000 successive fgetc is much slower than doing one single fread of 1000 bytes"
from question "Improve fgetc performance"