C Standard Library: Direct Input and Output Functions

1.5 Direct Input and Output Functions

size_t fread(void *ptr, size_t size, size_t nobj, FILE *stream)
fread reads from stream into the array ptr at most nobj objects of size size. fread
returns the number of objects read; this may be less than the number requested. feof
and ferror must be used to determine status.

size_t fwrite(const void *ptr, size_t size, size_t nobj, FILE *stream)
fwrite writes, from the array ptr, nobj objects of size size on stream. It returns the
number of objects written, which is less than nobj on error.