Properly initialize SF_INFO in example programs

Some of the example programs (examples/generate.c,
examples/sfprocess.c, examples/sndfile-to-text.c) didn't initialize
the SF_INFO structure to zero before using it, leading to undefined
behaviour. Add a memset() to fix this.

Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>

examples/generate.c

@@ -98,6 +98,8 @@ encode_file (const char *infilename, const char *outfilename, int filetype)
 	k = 16 - strlen (outfilename) ;
 	PUT_DOTS (k) ;
 
+	memset (&sfinfo, 0, sizeof (sfinfo)) ;
+
 	if (! (infile = sf_open (infilename, SFM_READ, &sfinfo)))
 	{	printf ("Error : could not open file : %s\n", infilename) ;
 		puts (sf_strerror (NULL)) ;

examples/sfprocess.c

@@ -60,7 +60,7 @@ main (void)
 	*/
 	SNDFILE	*infile, *outfile ;
 
-	/* A pointer to an SF_INFO stutct is passed to sf_open.
+	/* A pointer to an SF_INFO struct is passed to sf_open.
 	** On read, the library fills this struct with information about the file.
 	** On write, the struct must be filled in before calling sf_open.
 	*/
@@ -69,6 +69,10 @@ main (void)
 	const char	*infilename = "input.wav" ;
 	const char	*outfilename = "output.wav" ;
 
+	/* The SF_INFO struct must be initialized before using it.
+	*/
+	memset (&sfinfo, 0, sizeof (sfinfo)) ;
+
 	/* Here's where we open the input file. We pass sf_open the file name and
 	** a pointer to an SF_INFO struct.
 	** On successful open, sf_open returns a SNDFILE* pointer which is used

examples/sndfile-to-text.c

@@ -101,6 +101,8 @@ main (int argc, char * argv [])
 		return 1 ;
 		} ;
 
+	memset (&sfinfo, 0, sizeof (sfinfo)) ;
+
 	if ((infile = sf_open (infilename, SFM_READ, &sfinfo)) == NULL)
 	{	printf ("Not able to open input file %s.\n", infilename) ;
 		puts (sf_strerror (NULL)) ;