[lttng-dev] lttng-ust with --std=c99 -pedantic

[John Steele Scott]

I want to add lttng-ust tracepoints to a program which builds with "--std=c99 -pedantic". Right now this does not work.

Using the demo program as an example, if you enable --std=c99, the first issue looks like:

jscott at saaz:~/src/lttng-ust/tests/demo$ ccache gcc -std=c99 -DHAVE_CONFIG_H -I. -I../.. -I../../include/lttng  -I../../include -Wall -g -O2 -MT demo.o -MD -MP -MF .deps/demo.Tpo -c -o demo.o demo.c
In file included from demo.c:34:0:
ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___starting’:
ust_tests_demo.h:27:23: warning: implicit declaration of function ‘typeof’ [-Wimplicit-function-declaration]
ust_tests_demo.h:27:218: error: expected ‘;’ before ‘_________p1’
ust_tests_demo.h:27:395: error: ‘_________p1’ undeclared (first use in this function)
ust_tests_demo.h:27:395: note: each undeclared identifier is reported only once for each function it appears in
In file included from demo.c:34:0:
ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___done’:
ust_tests_demo.h:35:214: error: expected ‘;’ before ‘_________p1’
ust_tests_demo.h:35:383: error: ‘_________p1’ undeclared (first use in this function)
In file included from demo.c:35:0:
ust_tests_demo2.h: In function ‘__tracepoint_cb_ust_tests_demo2___loop’:
ust_tests_demo2.h:27:299: error: expected ‘;’ before ‘_________p1’
ust_tests_demo2.h:27:470: error: ‘_________p1’ undeclared (first use in this function)
In file included from demo.c:36:0:
ust_tests_demo3.h: In function ‘__tracepoint_cb_ust_tests_demo3___done’:
ust_tests_demo3.h:27:215: error: expected ‘;’ before ‘_________p1’
ust_tests_demo3.h:27:386: error: ‘_________p1’ undeclared (first use in this function)

This can be easily resolved by using __typeof__() instead of typeof(). Then I can build with --std=c99. But adding -pedantic still fails:

jscott at saaz:~/src/lttng-ust/tests/demo$ ccache gcc -std=c99 -Dtypeof=__typeof__ -pedantic -DHAVE_CONFIG_H -I. -I../.. -I../../include/lttng  -I../../include -Wall -g -O2 -MT demo.o -MD -MP -MF .deps/demo.Tpo -c -o demo.o demo.c
In file included from ust_tests_demo.h:25:0,
                 from demo.c:34:
../../include/lttng/tracepoint.h: In function ‘__tracepoints__init’:
../../include/lttng/tracepoint.h:251:4: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
../../include/lttng/tracepoint.h:255:4: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
../../include/lttng/tracepoint.h:260:4: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
../../include/lttng/tracepoint.h:264:4: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
../../include/lttng/tracepoint.h:268:4: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
In file included from demo.c:34:0:
ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___starting’:
ust_tests_demo.h:27:161: warning: ISO C forbids braced-groups within expressions [-pedantic]
ust_tests_demo.h:27:549: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
In file included from demo.c:34:0:
ust_tests_demo.h: In function ‘__tracepoint_cb_ust_tests_demo___done’:
ust_tests_demo.h:35:161: warning: ISO C forbids braced-groups within expressions [-pedantic]
ust_tests_demo.h:35:537: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
In file included from demo.c:35:0:
ust_tests_demo2.h: In function ‘__tracepoint_cb_ust_tests_demo2___loop’:
ust_tests_demo2.h:27:245: warning: ISO C forbids braced-groups within expressions [-pedantic]
ust_tests_demo2.h:27:624: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]
In file included from demo.c:36:0:
ust_tests_demo3.h: In function ‘__tracepoint_cb_ust_tests_demo3___done’:
ust_tests_demo3.h:27:161: warning: ISO C forbids braced-groups within expressions [-pedantic]
ust_tests_demo3.h:27:540: warning: ISO C forbids conversion of object pointer to function pointer type [-pedantic]

This is with 4.6.1-9ubuntu3 on Ubuntu 11.10, lttng-ust master 5a821c.

Would it be particularly difficult to make the lttng-ust tracepoints compatible with programs built with -pedantic?

cheers,

John