cc -pthread  -Wall -Wextra -Werror=implicit-function-declaration fcntl/posix_fallocate.c -o fcntl/posix_fallocate -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm -lpthread  -liconv
fcntl/posix_fallocate.c:16:16: error: call to undeclared function 'posix_fallocate'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
   16 |         if ( (errno = posix_fallocate(fileno(fp), 1, 2)) )
      |                       ^
1 error generated.