FREAD(3) BSD Library Functions Manual FREAD(3)
fread, fwrite -- binary stream input/output
Standard C Library (libc, -lc)
fread(void * restrict ptr, size_t size, size_t nmemb, FILE * restrict stream);
fwrite(const void * restrict ptr, size_t size, size_t nmemb, FILE * restrict stream);
The function fread() reads nmemb objects, each size bytes long, from the stream pointed to
by stream, storing them at the location given by ptr.
The function fwrite() writes nmemb objects, each size bytes long, to the stream pointed to
by stream, obtaining them from the location given by ptr.
The functions fread() and fwrite() advance the file position indicator for the stream by the
number of bytes read or written. They return the number of objects read or written. If an
error occurs, or the end-of-file is reached, the return value is a short object count (or
The function fread() does not distinguish between end-of-file and error, and callers must
use feof(3) and ferror(3) to determine which occurred. The function fwrite() returns a
value less than nmemb only if a write error has occurred.
read(2) , write(2)
The functions fread() and fwrite() conform to ISO/IEC 9899:1990 (``ISO C90'').
BSD March 8, 1994 BSD