Have you tried looking at a stack trace to see where your program is actually crashing? With the core file, you can even look at the value of variables, etc. Whenever I get a segmentation fault, the first thing I do is look at the stack trace to see where it happened. If you've never looked at a stack trace before, then you should probably take a look at the manual for GDB. They have a section on examining the stack. You'll also need to make sure that your programs are generating a core file when they crash. RedHat seems to have turned this off by default, but you can reenable it in the current shell using the ulimit command: ulimit -c unlimited Otherwise, I concur with what another poster said - you've probably corrupted memory before ever getting to this point, and this is just bringing the problem out. I would go over your code with a fine-toothed comb and look for any problems with pointers. Good luck, Lyle -----Original Message----- From: gcc-help-owner@xxxxxxxxxxx [mailto:gcc-help-owner@xxxxxxxxxxx]On Behalf Of Tobias Kretz Sent: Tuesday, January 13, 2004 3:32 AM To: gcc-help@xxxxxxxxxxx Subject: segmentation fault when allocating memory with new or malloc Hi, allocating memory with one of these lines: pl=(list*)malloc((v)*sizeof(list)); or list*pl; pl=new list[v]; causes the program to be terminated by a segmentation fault. v is an integer that equals e.g. 7 in my test runs (thus far from throwing a bad_alloc) and list is trivially: struct list{ int x; int y; double d; }; Replacing the variable v by a constant value does not improve the situation. Also: cout << "A\n"; try {pl=new list[v];} catch(bad_alloc) {cerr<< "not enough memory\n";} cout << "B\n"; results in the output: A Segmentation fault Additionally weird is that omitting the memory allocation makes the program run further. Yet it crashes with a seg fault. when trying to set up an outfile stream: bmpofstream image("floor.bmp",xmax,ymax); later in the program. The rest of the program contains datastructures for which I allcoate some 100kB memory (with new). I use g++, gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5) Regards, ToK
