spice-bitmap-utils.c has a lot of calls to fwrite() that don't check the
return value. On RHEL 6 these cause compilation errors due to -Werror:
spice-bitmap-utils.c:147: error: ignoring return value of 'fwrite',
declared with attribute warn_unused_result
What should be done about that?
* One option would be to remove -Werror but that would be really
heavy handed.
* I have not found a way to disable just that one warning. But if
others have more luck that could be an option.
* The best solution would be to not ignore the return values but that
means adding a lot of error-handling code. Does anyone want to take
this on?
* Otherwise the usual way to trick the compiler is to rewrite the code
as
(void)(func(...)+1)
It's really ugly so it is generally further hidden in a macro.
This would yield a patch somewhat like this:
diff --git a/server/spice-bitmap-utils.c b/server/spice-bitmap-utils.c
index 8d6e7c6..3cc8b35 100644
--- a/server/spice-bitmap-utils.c
+++ b/server/spice-bitmap-utils.c
@@ -30,6 +30,8 @@
#define GRADUAL_HIGH_RGB24_TH -0.03
#define GRADUAL_HIGH_RGB16_TH 0
+#define IGNORE(x) ((void)(x+1))
+
// setting a more permissive threshold for stream identification in order
// not to miss streams that were artificially scaled on the guest (e.g., full screen view
// in window media player 12). see red_stream_add_frame
@@ -141,7 +143,7 @@ static void dump_palette(FILE *f, SpicePalette* plt)
{
int i;
for (i = 0; i < plt->num_ents; i++) {
- fwrite(plt->ents + i, sizeof(uint32_t), 1, f);
+ IGNORE(fwrite(plt->ents + i, sizeof(uint32_t), 1, f));
}
}
@@ -150,11 +152,11 @@ static void dump_line(FILE *f, uint8_t* line, uint16_t n_pixel_bits, int width,
int i;
int copy_bytes_size = SPICE_ALIGN(n_pixel_bits * width, 8) / 8;
- fwrite(line, 1, copy_bytes_size, f);
+ IGNORE(fwrite(line, 1, copy_bytes_size, f));
if (row_size > copy_bytes_size) {
// each line should be 4 bytes aligned
for (i = copy_bytes_size; i < row_size; i++) {
- fprintf(f, "%c", 0);
+ IGNORE(fprintf(f, "%c", 0));
}
}
}
@@ -235,36 +237,36 @@ void dump_bitmap(SpiceBitmap *bitmap)
}
/* writing the bmp v3 header */
- fprintf(f, "BM");
- fwrite(&file_size, sizeof(file_size), 1, f);
+ IGNORE(fprintf(f, "BM"));
+ IGNORE(fwrite(&file_size, sizeof(file_size), 1, f));
tmp_u16 = alpha ? 1 : 0;
- fwrite(&tmp_u16, sizeof(tmp_u16), 1, f); // reserved for application
+ IGNORE(fwrite(&tmp_u16, sizeof(tmp_u16), 1, f)); // reserved for application
tmp_u16 = 0;
- fwrite(&tmp_u16, sizeof(tmp_u16), 1, f);
- fwrite(&bitmap_data_offset, sizeof(bitmap_data_offset), 1, f);
+ IGNORE(fwrite(&tmp_u16, sizeof(tmp_u16), 1, f));
+ IGNORE(fwrite(&bitmap_data_offset, sizeof(bitmap_data_offset), 1, f));
tmp_u32 = header_size - 14;
- fwrite(&tmp_u32, sizeof(tmp_u32), 1, f); // sub header size
+ IGNORE(fwrite(&tmp_u32, sizeof(tmp_u32), 1, f)); // sub header size
tmp_32 = bitmap->x;
- fwrite(&tmp_32, sizeof(tmp_32), 1, f);
+ IGNORE(fwrite(&tmp_32, sizeof(tmp_32), 1, f));
tmp_32 = bitmap->y;
- fwrite(&tmp_32, sizeof(tmp_32), 1, f);
+ IGNORE(fwrite(&tmp_32, sizeof(tmp_32), 1, f));
tmp_u16 = 1;
- fwrite(&tmp_u16, sizeof(tmp_u16), 1, f); // color plane
- fwrite(&n_pixel_bits, sizeof(n_pixel_bits), 1, f); // pixel depth
+ IGNORE(fwrite(&tmp_u16, sizeof(tmp_u16), 1, f)); // color plane
+ IGNORE(fwrite(&n_pixel_bits, sizeof(n_pixel_bits), 1, f)); // pixel depth
tmp_u32 = 0;
- fwrite(&tmp_u32, sizeof(tmp_u32), 1, f); // compression method
+ IGNORE(fwrite(&tmp_u32, sizeof(tmp_u32), 1, f)); // compression method
tmp_u32 = 0; //file_size - bitmap_data_offset;
- fwrite(&tmp_u32, sizeof(tmp_u32), 1, f); // image size
+ IGNORE(fwrite(&tmp_u32, sizeof(tmp_u32), 1, f)); // image size
tmp_32 = 0;
- fwrite(&tmp_32, sizeof(tmp_32), 1, f);
- fwrite(&tmp_32, sizeof(tmp_32), 1, f);
+ IGNORE(fwrite(&tmp_32, sizeof(tmp_32), 1, f));
+ IGNORE(fwrite(&tmp_32, sizeof(tmp_32), 1, f));
tmp_u32 = (!plt) ? 0 : plt->num_ents; // plt entries
- fwrite(&tmp_u32, sizeof(tmp_u32), 1, f);
+ IGNORE(fwrite(&tmp_u32, sizeof(tmp_u32), 1, f));
tmp_u32 = 0;
- fwrite(&tmp_u32, sizeof(tmp_u32), 1, f);
+ IGNORE(fwrite(&tmp_u32, sizeof(tmp_u32), 1, f));
if (plt) {
dump_palette(f, plt);
--
2.6.4
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