Clean up gz* function return values.

In some cases the return values did not match the documentation,
or the documentation did not document all of the return values.
gzprintf() now consistently returns negative values on error,
which matches the behavior of the stdio fprintf() function.
This commit is contained in:
Mark Adler
2016-12-03 08:18:56 -08:00
parent 9dc5a8585f
commit 123f9cfaf7
3 changed files with 37 additions and 34 deletions

26
zlib.h
View File

@@ -1355,10 +1355,12 @@ ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
/*
Dynamically update the compression level or strategy. See the description
of deflateInit2 for the meaning of these parameters.
of deflateInit2 for the meaning of these parameters. Previously provided
data is flushed before the parameter change.
gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
opened for writing.
gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not
opened for writing, Z_ERRNO if there is an error writing the flushed data,
or Z_MEM_ERROR if there is a memory allocation error.
*/
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
@@ -1401,15 +1403,15 @@ ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
/*
Converts, formats, and writes the arguments to the compressed file under
control of the format string, as in fprintf. gzprintf returns the number of
uncompressed bytes actually written, or 0 in case of error. The number of
uncompressed bytes written is limited to 8191, or one less than the buffer
size given to gzbuffer(). The caller should assure that this limit is not
exceeded. If it is exceeded, then gzprintf() will return an error (0) with
nothing written. In this case, there may also be a buffer overflow with
unpredictable consequences, which is possible only if zlib was compiled with
the insecure functions sprintf() or vsprintf() because the secure snprintf()
or vsnprintf() functions were not available. This can be determined using
zlibCompileFlags().
uncompressed bytes actually written, or a negative zlib error code in case
of error. The number of uncompressed bytes written is limited to 8191, or
one less than the buffer size given to gzbuffer(). The caller should assure
that this limit is not exceeded. If it is exceeded, then gzprintf() will
return an error (0) with nothing written. In this case, there may also be a
buffer overflow with unpredictable consequences, which is possible only if
zlib was compiled with the insecure functions sprintf() or vsprintf()
because the secure snprintf() or vsnprintf() functions were not available.
This can be determined using zlibCompileFlags().
*/
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));