beebe at math
Oct 12, 2009, 2:15 PM
Post #1 of 2
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gnupg-2.0.13: unwanted gcc-ism in source code, and a needed library
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I've made some further progress in getting gnupg-2.0.13 installed on
various local Unix platforms, and today, hit an apparent gcc-ism in
the source code:
% cd tests
% sed -n 202p asschk.c
#define die(format, args...) (die) ("%s: " format, __func__ , ##args) %%
Compiling this single file with gcc, and using the native compiler on
all other files, was sufficient to get this release on build on Sun
Solaris (SPARC, AMD64, and IA-32).
A check of the text of the 1999 ISO C Standard shows this
specification of the use of variable numbers of arguments in macro
definitions:
6.10.3 Macro replacement
...
4 If the identifier-list in the macro definition does not end with an
ellipsis, the number of arguments (including those arguments
consisting of no preprocessing tokens) in an invocation of a
function-like macro shall equal the number of parameters in the
macro definition. Otherwise, there shall be more arguments in the
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
invocation than there are parameters in the macro definition
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(excluding the ...). There shall exist a ) preprocessing token that
terminates the invocation.
The gnupg code seems to violate that highlighted requirement, since it
has subsequent statement like
die ("out of core");
die ("received line too large");
after the macro definition. Also, the Standard's syntax description
does not appear to permit a comma to be omitted before the ellipsis.
The Sun c99 compiler on this test file
% cat foo-die.c
extern void die (const char *format, ...);
#define die(format, args, ...) (die) ("%s: " format, __func__ , ##args)
void
foo()
{
die("test 1"); /* line 8 */
die("test 1", "test 2"); /* line 9 */
die("test 1", "test 2", "test 3"); /* line 10 */
}
produces these errors:
% c99 -c foo-die.c
"foo-die.c", line 8: warning: argument mismatch
"foo-die.c", line 8: syntax error before or at: )
"foo-die.c", line 9: warning: argument mismatch
c99: acomp failed for foo-die.c
Notice that lines 8 and 9 elicit a diagnostic, but line 10, which has
the required minimum number of arguments, does not.
Inasmuch as this is the ONLY file in this gnupg release that uses this
C99 feature, I suggest that it would be better to remove it, in the
interests of gnupg being compilable by a wider range of compilers.
Also, linking of this release on Solaris fails with nanosleep()
unresolved. Restarting the build with
make LIBS=-lrt
resolves that problem. The -lrt (real-time) library is needed on
several systems for features like high-precision timers, so configure
scripts should be written to find whether -lrt is needed on a given
build host.
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- University of Utah FAX: +1 801 581 4148 -
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