X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=functions%2Fstdio%2F_PDCLIB_prepwrite.c;fp=functions%2Fstdio%2F_PDCLIB_prepwrite.c;h=1b1c4b526eecceee5105e9ef544aa761d2928bcc;hb=3082b97d8f2de1584430ad42671a0e056ed33be4;hp=0000000000000000000000000000000000000000;hpb=d7f27d5325d7c44d93be00662b13aa9ffdec76b1;p=pdclib

diff --git a/functions/stdio/_PDCLIB_prepwrite.c b/functions/stdio/_PDCLIB_prepwrite.c
new file mode 100644
index 0000000..1b1c4b5
--- /dev/null
+++ b/functions/stdio/_PDCLIB_prepwrite.c
@@ -0,0 +1,42 @@
+/* $Id$ */
+
+/* _PDCLIB_prepwrite( struct _PDCLIB_file_t * )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <stdio.h>
+#include <errno.h>
+
+#ifndef REGTEST
+int _PDCLIB_prepwrite( struct _PDCLIB_file_t * stream )
+{
+    if ( ( stream->bufidx < stream->bufend ) || ( stream->ungetidx > 0 ) ||
+         ( stream->status & ( _PDCLIB_FREAD | _PDCLIB_ERRORFLAG | _PDCLIB_WIDESTREAM | _PDCLIB_EOFFLAG ) ) ||
+         ! ( stream->status & ( _PDCLIB_FWRITE | _PDCLIB_FAPPEND | _PDCLIB_FRW ) ) )
+    {
+        /* Function called on illegal (e.g. input) stream.
+           See the comments on implementation-defined errno values in
+           <_PDCLIB_config.h>.
+        */
+        errno = EINVAL;
+        stream->status |= _PDCLIB_ERRORFLAG;
+        return EOF;
+    }
+    stream->status |= _PDCLIB_FWRITE | _PDCLIB_BYTESTREAM;
+    return 0;
+}
+#endif
+
+#ifdef TEST
+#include <_PDCLIB_test.h>
+
+int main( void )
+{
+    /* Testing covered by ftell.c */
+    return TEST_RESULTS;
+}
+
+#endif
+