fread
Synopsis
#include <stdio.h>
size_t fread(void *restrict ptr, size_t size, size_t nitems, FILE *restrict stream);
Status
Partially implemented
Conformance
IEEE Std 1003.1-2017
Description
The fread() function shall read into the array pointed to by ptr up to nitems elements whose size is specified by
size in bytes, from the stream pointed to by stream. For each object, size calls shall be made to the fgetc()
function and the results stored, in the order read, in an array of unsigned char exactly overlaying the object. The
file position indicator for the stream (if defined) shall be advanced by the number of bytes successfully read. If an
error occurs, the resulting value of the file position indicator for the stream is unspecified. If a partial element is
read, its value is unspecified.
The fread() function may mark the last data access timestamp of the file associated with stream for update. The last
data access timestamp shall be marked for update by the first successful execution of fgetc(), fgets(), fread(),
fscanf(), getc(), getchar(), getdelim(), getline(), gets(), or scanf() using stream that returns data
not supplied by a prior call to ungetc().
Return value
Upon successful completion, fread() shall return the number of elements successfully read which is less than nitems
only if a read error or end-of-file is encountered. If size or nitems is 0, fread() shall return 0 and the
contents of the array and the state of the stream remain unchanged. Otherwise, if a read error occurs, the error
indicator for the stream shall be set and errno shall be set to indicate the error.
Errors
Refer to fgetc
Tests
Untested
Known bugs
None