fix assumption in fputs that fwrite returning 0 implies an error

internally, the idiom of passing nmemb=1 to fwrite and interpreting
the return value of fwrite (which is necessarily 0 or 1) as
failure/success is fairly widely used. this is not correct, however,
when the size argument is unknown and may be zero, since C requires
fwrite to return 0 in that special case. previously fwrite always
returned nmemb on success, but this was changed for conformance with
ISO C by commit 500c6886c654fd45e4926990fee2c61d816be197.

diff --git a/src/stdio/fputs.c b/src/stdio/fputs.c
index 4737f448e934ac18465c4f827b479edabcc180d4..1cf344f28c6fe88a9394ef64ebe25ea0fbdcf74a 100644 (file)
--- a/src/stdio/fputs.c
+++ b/src/stdio/fputs.c
@@ -3,7 +3,8 @@
 
 int fputs(const char *restrict s, FILE *restrict f)
 {
-       return (int)fwrite(s, strlen(s), 1, f) - 1;
+       size_t l = strlen(s);
+       return (fwrite(s, 1, l, f)==l) - 1;
 }
 
 weak_alias(fputs, fputs_unlocked);