"Alex Vinokur" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > > "Igor Pechtchanski" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > [snip] > > > > Umm, Elfyn, the semantics of "assert()" is that you assert some predicate > > to be true. If the predicate is indeed true, the program continues > > normally. If the predicate is false, the program fails. > > The predicate in this case is "ptr != MAP_FAILED". Thus, the predicate > > was false when the assertion failed, and ptr == MAP_FAILED. > > > > To the OP: this means that mmap() did fail for some reason. It should > > have set errno to indicate why. You should check that instead of > > asserting -- mmap does fail occasionally. Also FYI, once you assert, the > > following test for "ptr != MAP_FAILED" is redundant -- the program will > > not get there otherwise. > > Igor > [snip] > > > Here is updated function. > -------------------------------------- > void read_file (char* filename_i) > { > int fd = open(filename_i, O_RDONLY); > assert (fd > 2); > > off_t sz = lseek(fd, 0, SEEK_END); errno = 0; > char* ptr = (char*)mmap(0, sz, PROT_READ, 0, fd, 0); > -------------------------------- Must be removed > errno = 0; -------------------------------- > if (ptr != MAP_FAILED) > { > string str(ptr, ptr+sz); > munmap(ptr, sz); > } > else > { > assert (ptr == MAP_FAILED); > printf ("=== Error : %u %s ===\n", errno, strerror (errno)); > } > assert (ptr != MAP_FAILED); // Here assertion failed > > close(fd); > } > -------------------------------------- > > The program prints: === Error : 22 Invalid argument ===
Which argument? [snip] ========================================== Alex Vinokur mailto:[EMAIL PROTECTED] http://www.simtel.net/pub/oth/19088.html http://sourceforge.net/users/alexvn ========================================== -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/