FREAD(3) Linux Programmer's Manual FREAD(3)
fread, fwrite - binary stream input/output
size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
size_t fwrite(const void *ptr, size_t size, size_t nmemb,
The function fread() reads nmemb elements of data, each size bytes long, from the stream
pointed to by stream, storing them at the location given by ptr.
The function fwrite() writes nmemb elements of data, each size bytes long, to the stream
pointed to by stream, obtaining them from the location given by ptr.
For nonlocking counterparts, see unlocked_stdio(3).
On success, fread() and fwrite() return the number of items read or written. This number
equals the number of bytes transferred only when size is 1. If an error occurs, or the
end of the file is reached, the return value is a short item count (or zero).
fread() does not distinguish between end-of-file and error, and callers must use feof(3)
and ferror(3) to determine which occurred.
read(2), write(2), feof(3), ferror(3), unlocked_stdio(3)
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GNU 2012-03-30 FREAD(3)