straced the following c code: // a01.c #include int main() { int pipefd[2]; if (pipe2(pipefd, 0) == -1) { perror("pipe"); exit(EXIT_FAILURE); } return 0; } $ gcc a01.c; strace -o trace2.txt ./a.out pipe: Function not implemented trace2.txt output: execve("./a.out", ["./a.out", "aa"], [/* 26 vars */]) = 0 brk(0) = 0x804a000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f95000 access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) open("/etc/ld.so.cache", O_RDONLY) = 3 fstat64(3, {st_mode=S_IFREG|0644, st_size=33271, ...}) = 0 mmap2(NULL, 33271, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb7f8c000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/i686/cmov/libc.so.6", O_RDONLY) = 3 read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\320m\1\0004\0\0\0"..., 512) = 512 fstat64(3, {st_mode=S_IFREG|0755, st_size=1323460, ...}) = 0 mmap2(NULL, 1333608, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb7e46000 mmap2(0xb7f86000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x13f) = 0xb7f86000 mmap2(0xb7f89000, 10600, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb7f89000 close(3) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7e45000 set_thread_area({entry_number:-1 -> 6, base_addr:0xb7e456c0, limit:1048575, seg_32bit:1, contents:0, read_exec_only:0, limit_in_pages:1, seg_not_present:0, useable:1}) = 0 open("/dev/urandom", O_RDONLY) = 3 read(3, "\315\1\201", 3) = 3 close(3) = 0 mprotect(0xb7f86000, 8192, PROT_READ) = 0 mprotect(0xb7fb2000, 4096, PROT_READ) = 0 munmap(0xb7f8c000, 33271) = 0 pipe2(0xbffb2dd8, 0) = -1 ENOSYS (Function not implemented) dup(2) = 3 fcntl64(3, F_GETFL) = 0x2 (flags O_RDWR) brk(0) = 0x804a000 brk(0x806b000) = 0x806b000 fstat64(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 4), ...}) = 0 mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f94000 _llseek(3, 0, 0xbffb2c58, SEEK_CUR) = -1 ESPIPE (Illegal seek) write(3, "pipe: Function not implemented\n", 31) = 31 close(3) = 0 munmap(0xb7f94000, 4096) = 0 exit_group(1) = ?