Re: Problem with 'struct timespec' and C99 standard

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Hi, Eljay!

Thanks for the answer!

Summary of the following posting:
'-D_POSIX_SOURCE' does not help
'-D_POSIX_C_SOURCE 199309L' helps

Box with Intel ompiler is not available at the moment, can not tell the
difference between gcc and icc.

intro: "EL" == Eljay Love-Jensen <eljay@xxxxxxxxx> writes:

  EL> Hi Nickolay, The time.h header file is not part of GCC, it is supplied by
  EL> the OS.

Yes, it is part of glibc (glibc-2.3 in my case)

  EL> The timespec structure is part of POSIX P1003.1b-1993 specification.

  EL> Does -D_POSIX_SOURCE change anything when you've -std=c99 ?

No, plain -D_POSIX_SOURCE does not help.  Output:
-------------------------------------------------------------------------------
$ gcc -v -D_POSIX_SOURCE -std=c99 -c t.c
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --host=i386-redhat-linux
Thread model: posix
gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/cc1 -lang-c -v -D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=2 -D__GXX_ABI_VERSION=102 -D__ELF__ -D__unix__ -D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -D__i386 -D__i386__ -D__tune_i386__ -D_POSIX_SOURCE t.c -quiet -dumpbase t.c -std=c99 -version -o /tmp/ccg6vab1.s
GNU CPP version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (cpplib) (i386 Linux/ELF)
GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (i386-redhat-linux)
        compiled by GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5).
ignoring nonexistent directory "/usr/i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/include
 /usr/include
End of search list.
t.c:4: storage size of `t' isn't known
-------------------------------------------------------------------------------

-D_POSIX_C_SOURCE 199309L works (taken from glibc manual)

$ gcc -v -D_POSIX_C_SOURCE=199309L -std=c99 -c t.c
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --host=i386-redhat-linux
Thread model: posix
gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/cc1 -lang-c -v -D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=2 -D__GXX_ABI_VERSION=102 -D__ELF__ -D__unix__ -D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -D__i386 -D__i386__ -D__tune_i386__ -D_POSIX_C_SOURCE=199309L t.c -quiet -dumpbase t.c -std=c99 -version -o /tmp/ccLQS7rJ.s
GNU CPP version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (cpplib) (i386 Linux/ELF)
GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (i386-redhat-linux)
        compiled by GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5).
ignoring nonexistent directory "/usr/i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/include
 /usr/include
End of search list.
 as -V -Qy -o t.o /tmp/ccLQS7rJ.s
GNU assembler version 2.13.90.0.18 (i386-redhat-linux) using BFD version 2.13.90.0.18 20030206


  EL> You may want to use -v to see what's going on with the command-line under
  EL> the covers.  Compare "gcc -v -std=c99 -c t.c" versus "gcc -v -std=gnu99
  EL> -c t.c", and see what kinds of freebie command line flags you're getting
  EL> under the covers.

difference in cc1 invocation:
-std=gnu99 adds the followin defines:
 -D__gnu_linux__ -Di386 -Dlinux -Dunix

Log for -std=c99
-------------------------------------------------------------------------------
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --host=i386-redhat-linux
Thread model: posix
gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/cc1 -lang-c -v -D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=2 -D__GXX_ABI_VERSION=102 -D__ELF__ -D__unix__ -D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -D__i386 -D__i386__ -D__tune_i386__ t.c -quiet -dumpbase t.c -std=c99 -version -o /tmp/ccpl8I8j.s
GNU CPP version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (cpplib) (i386 Linux/ELF)
GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (i386-redhat-linux)
	compiled by GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5).
ignoring nonexistent directory "/usr/i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/include
 /usr/include
End of search list.
t.c:4: storage size of `t' isn't known
-------------------------------------------------------------------------------
Log for -std=gnu99
-------------------------------------------------------------------------------
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --host=i386-redhat-linux
Thread model: posix
gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/cc1 -lang-c -v -D__GNUC__=3 -D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=2 -D__GXX_ABI_VERSION=102 -D__ELF__ -Dunix -D__gnu_linux__ -Dlinux -D__ELF__ -D__unix__ -D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asystem=posix -D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386 -D__i386 -D__i386__ -D__tune_i386__ t.c -quiet -dumpbase t.c -std=gnu99 -version -o /tmp/ccxs3CeY.s
GNU CPP version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (cpplib) (i386 Linux/ELF)
GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) (i386-redhat-linux)
	compiled by GNU C version 3.2.2 20030222 (Red Hat Linux 3.2.2-5).
ignoring nonexistent directory "/usr/i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i386-redhat-linux/3.2.2/include
 /usr/include
End of search list.
 as -V -Qy -o t.o /tmp/ccxs3CeY.s
GNU assembler version 2.13.90.0.18 (i386-redhat-linux) using BFD version 2.13.90.0.18 20030206
-------------------------------------------------------------------------------

  EL> HTH, --Eljay


Nick.



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