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POHow to use GDB inside giant loops
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2013-10-25T22:19:55.627
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I have the following loop and my code breaks but I don't know at which iteration it breaks exactly. <pre><code>int n=1000; for (i=0; i<n; i++) { slot = random() % max_allocs; doAlloc = random() % 4; doWrite = writeData; if (!doAlloc || ptr[slot] != NULL) { if (ptr[slot] == NULL) ;//assert(Mem_Free(ptr[slot]) == -1); else { printf("I got here \n"); printf("mem free ptr slot is %d \n",Mem_Free(ptr[slot])); } free(shadow[slot]); ptr[slot] = NULL; shadow[slot] = NULL; } if (doAlloc) { size[slot] = min_alloc_size + (random() % (max_alloc_size - min_alloc_size + 1)); printf("size[slot] :%d\n", size[slot]); ptr[slot] = Mem_Alloc(size[slot], BESTFIT); printf("ptr slot is %p \n",ptr[slot]); assert(ptr[slot] != NULL); if (doWrite) { shadow[slot] = malloc(size[slot]); int j; for (j=0; j<size[slot]; j++) { char data = random(); *((char*)(ptr[slot] + j)) = data; *((char*)(shadow[slot] + j)) = data; } } } } </code></pre> How can I find at which iteration of n the code breaks and how can I put a breakpoint at that iteration? P.S.: Is there any other better debugger for this purpose in Linux? (If I don't want to use Eclipse!) Here's the error I am receiving in gdb: <pre><code>mymain: mymain.c:104: main: Assertion `ptr[slot] != ((void *)0)' failed. Program received signal SIGABRT, Aborted. 0x000000368da328e5 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 64 return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig); (gdb) backtrace #0 0x000000368da328e5 in raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 #1 0x000000368da340c5 in abort () at abort.c:92 #2 0x000000368da2ba0e in __assert_fail_base (fmt=<value optimized out>, assertion=0x40114b "ptr[slot] != ((void *)0)", file=0x401142 "mymain.c", line=<value optimized out>, function=<value optimized out>) at assert.c:96 #3 0x000000368da2bad0 in __assert_fail (assertion=0x40114b "ptr[slot] != ((void *)0)", file=0x401142 "mymain.c", line=104, function=0x401199 "main") at assert.c:105 #4 0x0000000000400e2a in main (argc=4, argv=0x7fffffffdb68) at mymain.c:104 (gdb) frame 1 #1 0x000000368da340c5 in abort () at abort.c:92 92 raise (SIGABRT); (gdb) frame 3 #3 0x000000368da2bad0 in __assert_fail (assertion=0x40114b "ptr[slot] != ((void *)0)", file=0x401142 "mymain.c", line=104, function=0x401199 "main") at assert.c:105 105 __assert_fail_base (_("%s%s%s:%u: %s%sAssertion `%s' failed.\n%n"), </code></pre>
Tags
<c><linux><debugging><gdb><breakpoints>
Title
How to use GDB inside giant loops
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1. USMona Jalal
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1. USMona Jalal
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