What does the postfix "_t" stand for in C? [duplicate]
The t stands for "type" or "typedef." You'll see a lot of POSIX headers (and others) with time_t, size_t, and others. These which hold (not necessarily defined) specific bit-sizes based on the operating system and machine architecture.
based only on my own experience, the "_t" postfix means "data type". In other words, it's a datatype defined used typedef.
The "_t" suffix is a convention for data type names such as size_t or wchar_t. It's not used consistently.