Hi Nickolay, The time.h header file is not part of GCC, it is supplied by the OS. The timespec structure is part of POSIX P1003.1b-1993 specification. Does -D_POSIX_SOURCE change anything when you've -std=c99 ? You may want to use -v to see what's going on with the command-line under the covers. Compare "gcc -v -std=c99 -c t.c" versus "gcc -v -std=gnu99 -c t.c", and see what kinds of freebie command line flags you're getting under the covers. HTH, --Eljay
