Unknown type name 'siginfo_t' with Clang using _POSIX_C_SOURCE 2, why?

Question

Refresh . My teacher accepts code written in the GNU99 standard, so as user1 pointed out, I used it _GNU_SOURCEat the beginning of my program. (See man feature_test_macrosfor more information.) Thanks for helping me understand!

On Ubuntu 13.10 with Clang 3.4, GCC 4.8.1, I am doing a task that requires me to use the C99 standard. (I also have GNUstep installed from SVN)

WRT GCC, I think I have 4 versions installed in these folders:

/usr/lib/gcc/x86_64-linux-gnu/4.7
/usr/lib/gcc/x86_64-linux-gnu/4.7.3
/usr/lib/gcc/x86_64-linux-gnu/4.8
/usr/lib/gcc/x86_64-linux-gnu/4.8.1

gcc --versionreports reports 4.8.1, clang --version3.4. ld -vreports 2.23.52.20130913

I write a signal handler, and when I use siginfo_t in the function header, I get a compiler error: unknown type name 'siginfo_t'I use sigaction () to set the handler.

By learning what to do and how, I was able to compile a simple demo that also uses the same function header definition, and it works. However, this is not limited to C99.

These are my included ones (of which signal.h is one):

#define _POSIX_C_SOURCE 2

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <math.h>
#include <ctype.h>
#include <libgen.h>
#include <signal.h>

This is my signal handler function (for debugging purposes only):

static void sigSIGCHLDhandler(int sigNum, siginfo_t *siginfo, void *context) {

        printf("PID = %ld",(long) siginfo->si_pid);

}

I compile with clangusing -Walland are now options. -std=c99-std=gnu99

I tried locate signal.h, and I have it in /usr/include. I tried to add #include <bits/siginfo.h>, and this allowed me to compile, but the binary will not work correctly.
(My system has a bunch of files signal.hand siginfo.h.)

, - . Clang. , , , (, , - )

LD_LIBRARY_PATH=/home/user/ros_catkin_ws/install_isolated/lib:/home/user/GNUstep/Library/Libraries:/usr/local/lib
CPATH=/home/user/ros_catkin_ws/install_isolated/include
PATH=/home/user/ros_catkin_ws/install_isolated/bin:/home/user/GNUstep/Tools:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/home/user/bin:/usr/local/java/jdk1.7.0_51/bin
CLASSPATH=/home/user/GNUstep/Library/Libraries/Java:/usr/local/lib/GNUstep/Libraries/Java
LIBRARY_COMBO=gnu-gnu-gnu
INFOPATH=/usr/local/share/info::/home/user/GNUstep/Library/Documentation/info:
GNUSTEP_IS_FLATTENED=yes
GNUSTEP_LOCAL_ROOT=/usr/local/Local
GNUSTEP_HOST=x86_64-unknown-linux-gnu
GUILE_LOAD_PATH=/home/user/GNUstep/Library/Libraries/Guile:/usr/local/lib/GNUstep/Libraries/Guile
GNUSTEP_MAKEFILES=/usr/local/share/GNUstep/Makefiles
GNUSTEP_NETWORK_ROOT=/usr/local/Network
GNUSTEP_FLATTENED=yes
GNUSTEP_HOST_OS=linux-gnu
GNUSTEP_HOST_VENDOR=unknown
GNUSTEP_HOST_CPU=x86_64
GNUSTEP_USER_ROOT=/home/user/GNUstep
GNUSTEP_SYSTEM_ROOT=/usr/local/System
GNUSTEP_PATHLIST=/usr/local/System:/usr/local/Network:/usr/local/Local:/home/user/GNUstep
GNUSTEP_SYSTEM_ROOT=/usr/local/System
GNUSTEP_PATHLIST=/usr/local/System:/usr/local/Network:/usr/local/Local:/home/nap/GNUstep

, , . ?

Answer 1

man- sigaction (2), :

siginfo_t: _POSIX_C_SOURCE >= 199309L

: -D_POSIX_C_SOURCE=199309L

posix c-lib (glibc).

EDIT:

Wiki POSIX.

featuers.h , glibc :

   _POSIX_C_SOURCE  
          If ==1, like _POSIX_SOURCE; 
          if >=2 add IEEE Std 1003.2;
          if >=199309L, add IEEE Std 1003.1b-1993;
          if >=199506L, add IEEE Std 1003.1c-1995;
          if >=200112L, all of IEEE 1003.1-2004

man: feature_test_macros (7).

: _POSIX_C_SOURCE = 2 POSIX , 1003.2 (posix 2) . , .

: POSIX.2 , POSIX.1c.