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Fix fwrite() to return 0 when size or nmemb are zero.

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Right now nmemb is returned when size is 0. In newer versions of the
standards, it is explicitly required that fwrite() should return 0.

Submitted by:	Christoph Mallon
Approved by:	re (kib)
This commit is contained in:
Ed Schouten 2009-07-12 13:09:43 +00:00
parent 5861f96654
commit 77822acff7
2 changed files with 9 additions and 4 deletions
lib/libc/stdio
fread.cfwrite.c

4
lib/libc/stdio/fread.c

@ -67,9 +67,7 @@ __fread(void * __restrict buf, size_t size, size_t count, FILE * __restrict fp)
size_t total;
/*
* The ANSI standard requires a return value of 0 for a count
* or a size of 0. Peculiarily, it imposes no such requirements
* on fwrite; it only requires fread to be broken.
* ANSI and SUSv2 require a return value of 0 if size or count are 0.
*/
if ((resid = count * size) == 0)
return (0);

9
lib/libc/stdio/fwrite.c

@ -57,8 +57,15 @@ fwrite(buf, size, count, fp)
struct __suio uio;
struct __siov iov;
/*
* ANSI and SUSv2 require a return value of 0 if size or count are 0.
*/
n = count * size;
if (n == 0)
return (0);
iov.iov_base = (void *)buf;
uio.uio_resid = iov.iov_len = n = count * size;
uio.uio_resid = iov.iov_len = n;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;