Thread: gdb debug issues

Hi Guys

I am trying to print out the value of a variable after a segmentation fault. However no matter what i try cannot get the values printed out. I have tried print XX, to no avail. The variables should all be in scope. I have also tried the print ZZ:XX where ZZ is the function name. I switched off all compiler optimisation trying absence of any command and also -O0. I cannot print anything out!

Here is the gdb output from running the program

Code:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000411167 in R2MinImageCo ()
(gdb) bt
#0  0x0000000000411167 in R2MinImageCo ()
#1  0x0000000000411bc5 in CalculatePairwiseEnergyNonBondedEnergyCell ()
#2  0x000000000040b30f in MonteCarloRunComb ()
#3  0x0000000000418892 in main ()
(gdb) info registers
rax            0x65f1   26097
rbx            0x7      7
rcx            0x40366a161e4f7660       4627002310400112224
rdx            0x13a9b80        20618112
rsi            0x3      3
rdi            0x7fff297afd50   140733889314128
rbp            0x7fff29789220   0x7fff29789220
rsp            0x7fff297891d0   0x7fff297891d0
r8             0x7fff297afd50   140733889314128
r9             0xd13940 13711680
r10            0x192    402
r11            0x7      7
r12            0x8      8
r13            0x7fff297892b0   140733889155760
r14            0x40366a161e4f7660       4627002310400112224
r15            0xd0f930 13695280
rip            0x411167 0x411167 <R2MinImageCo(double***, int, int, double, double, double)+83>
eflags         0x10283  [ CF SF IF RF ]
cs             0x33     51
ss             0x2b     43
ds             0x0      0
es             0x0      0
fs             0x0      0
gs             0x0      0
fctrl          0x37f    895
fstat          0x0      0
ftag           0xffff   65535
fiseg          0x0      0
fioff          0x4137be 4274110
foseg          0x7fff   32767
fooff          0x297952b8       695816888
fop            0x1c9    457
mxcsr          0x1fa2   [ DE PE IM DM ZM OM UM PM ]

Now I wish to obtain a variable that is passed into R2MinImageCo() function. However I cannot seem to find any of these variables. I include the function prototype here:

double R2MinImageCo(double ***ptrBeadArray, int FinalBeadIndex, int InitialBeadIndex, double Xbox, double Ybox, double Zbox)

so I am trying

Code:

(gdb) print FinalBeadIndex
No symbol "FinalBeadIndex" in current context.

(gdb) print R2MinImageCo
$1 = {<text variable, no debug info>} 0x411114 <R2MinImageCo(double***, int, int, double, double, double)>

(gdb) print R2MinImageCo::FinalBeadIndex
A syntax error in expression, near `::FinalBeadIndex'.

(gdb) print 'R2MinImageCo::FinalBeadIndex'
No symbol "R2MinImageCo::FinalBeadIndex" in current context.
(gdb) print `R2MinImageCo::FinalBeadIndex`
Invalid character '`' in expression.

(gdb) print R2MinImageCo::xdiff
A syntax error in expression, near `::xdiff'.

Any ideas how I can achieve these values to be outputted? Thanks!

Did you use -g? (I'm guessing since it says "no debug info" the answer is "no". You should.)