Obtain backtrace by programming

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When you use the gdb debugger, you can view the so-called backtrace, which contains a series of function call Information. You can use the command backtrace or BT to view the function call stack information in GDB. In some cases, you can use some related functions in the glibc library function to obtain backtrace information (in the header file execinfo. h ):

// Obtain and save the backstrace information to the buffer. // The parameter size specifies the maximum value of the buffer. The returned value is the actual size of backstrace. Int backtrace (void ** buffer, int size)   // Return the symbolic information based on the address specified by the buffer. Parameter size specifies the size of the returned Symbol Information Char ** backtrace_symbols (void * const * buffer, int size)   // Similar to the backtrace_symbols () function, but the malloc space is not required to store the symbol information, // Write the result to the file represented by the file descriptor FD. Void backtrace_symbols_fd (void * const * buffer, int size, int FD)

When using the backtrace_symbols () or backtrace_symbols_fd () function, you must use-rdynamic compilation to get the correct symbol name. Otherwise, you can only get the offset address.

The following sample code applies the backtrace () and backtrace_symbols () functions to print backtrace information:

1 # include <execinfo. h> 2 # include <stdio. h> 3 # include <stdlib. h> 4 5/* obtain a backtrace and print it to stdout .*/ 6 void print_trace (void) 7 { 8 void * array [10]; 9 size_t size; 10 char ** strings; 11 size_t I; 12 13 size = backtrace (array, 10 ); 14 strings = backtrace_symbols (array, size ); 15 16 printf ("obtained % ZD stack frames./N", size ); 17 18 For (I = 0; I <size; I ++) 19 printf ("% s/n", strings [I]); 20 21 free (strings ); 22} 23 24/* a dummy function to make the backtrace more interesting .*/ 25 void dummy_function (void) 26 { 27 print_trace (); 28} 29 30 int main (void) 31 { 32 dummy_function (); 33 return 0; 34}

The compilation and running results are as follows:

# GCC Bt. C-rdynamic-O BT #./BT Obtained 5 stack frames. ./Bt (print_trace + 0x14) [0x80486e4] ./Bt (dummy_function + 0xb) [0x8048765] ./Bt (main + 0x15) [0x 804877c ] /Lib/tls/libc. so.6 (_ libc_start_main + 0xe4) [0x42015574] ./Bt (backtrace_symbols + 0x31) [0x8048641]

You can apply these functions to print backtrace when the program exits unexpectedly or save it to a file for later analysis. For more information, see http://www.linuxjournal.com/article/6391.