運行包含'nullify'的FORTRAN代碼時發生Linux錯誤

Question

幾天前我開始學習FORTRAN，並且在試圖'取消'指針時偶然發現錯誤。代碼編譯時沒有任何缺陷，但是這是它在輸入變量後顯示的內容。我也知道這個問題是由'nullify'命令引起的，因爲如果我評論該行，程序運行時沒有任何錯誤。

代碼：

program demo1 
    implicit none 
    TYPE :: Neuron 
     real :: val = 0 
     real :: w1 = 1, w2 = 1 
     TYPE(Neuron), pointer :: vertex1, vertex2 
    end TYPE Neuron 

    TYPE :: container 
     TYPE(Neuron), pointer :: obj 
    end TYPE container 

    integer :: i=0, n_inputs 
    TYPE(Neuron), target :: output_vertex 
    TYPE(Neuron), pointer :: temp 
    TYPE(container), allocatable, dimension(:) :: inputs 

    read (*,*) n_inputs 

    allocate(inputs(0:n_inputs)) 

    inputs(0)%obj=>output_vertex 

    !do i=1, n_inputs 
     temp=>inputs(i-1)%obj 

     nullify(inputs(i-1)%obj) 
     !allocate(inputs(i)%obj) 
     !allocate(inputs(i-1)%obj) 

     !temp%vertex1=>inputs(i)%obj 
     !temp%vertex2=>inputs(i-1)%obj 
    !end do 

end program demo1 

錯誤輸出：

*** glibc detected *** ./demo1.o: free(): invalid pointer: 0x08dafc18 *** 
======= Backtrace: ========= 
/lib/i386-linux-gnu/libc.so.6(+0x75ee2)[0xb74b8ee2] 
./demo1.o[0x8048855] 
./demo1.o[0x8048899] 
/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf3)[0xb745c4d3] 
./demo1.o[0x80485e1] 
======= Memory map: ======== 
08048000-08049000 r-xp 00000000 08:02 2621510 /media/work/teme/neural_network/demo1.o 
08049000-0804a000 r--p 00000000 08:02 2621510 /media/work/teme/neural_network/demo1.o 
0804a000-0804b000 rw-p 00001000 08:02 2621510 /media/work/teme/neural_network/demo1.o 
08dac000-08dcd000 rw-p 00000000 00:00 0   [heap] 
b7370000-b738c000 r-xp 00000000 08:01 4195265 /lib/i386-linux-gnu/libgcc_s.so.1 
b738c000-b738d000 r--p 0001b000 08:01 4195265 /lib/i386-linux-gnu/libgcc_s.so.1 
b738d000-b738e000 rw-p 0001c000 08:01 4195265 /lib/i386-linux-gnu/libgcc_s.so.1 
b73a1000-b73a2000 rw-p 00000000 00:00 0 
b73a2000-b73cc000 r-xp 00000000 08:01 4199147 /lib/i386-linux-gnu/libm-2.15.so 
b73cc000-b73cd000 r--p 00029000 08:01 4199147 /lib/i386-linux-gnu/libm-2.15.so 
b73cd000-b73ce000 rw-p 0002a000 08:01 4199147 /lib/i386-linux-gnu/libm-2.15.so 
b73ce000-b7440000 r-xp 00000000 08:01 3150891 /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0 
b7440000-b7441000 r--p 00071000 08:01 3150891 /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0 
b7441000-b7442000 rw-p 00072000 08:01 3150891 /usr/lib/i386-linux-gnu/libquadmath.so.0.0.0 
b7442000-b7443000 rw-p 00000000 00:00 0 
b7443000-b75e7000 r-xp 00000000 08:01 4199152 /lib/i386-linux-gnu/libc-2.15.so 
b75e7000-b75e9000 r--p 001a4000 08:01 4199152 /lib/i386-linux-gnu/libc-2.15.so 
b75e9000-b75ea000 rw-p 001a6000 08:01 4199152 /lib/i386-linux-gnu/libc-2.15.so 
b75ea000-b75ed000 rw-p 00000000 00:00 0 
b75ed000-b76eb000 r-xp 00000000 08:01 3154416 /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0 
b76eb000-b76ec000 r--p 000fe000 08:01 3154416 /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0 
b76ec000-b76ed000 rw-p 000ff000 08:01 3154416 /usr/lib/i386-linux-gnu/libgfortran.so.3.0.0 
b76ed000-b76ee000 rw-p 00000000 00:00 0 
b7700000-b7703000 rw-p 00000000 00:00 0 
b7703000-b7704000 r-xp 00000000 00:00 0   [vdso] 
b7704000-b7724000 r-xp 00000000 08:01 4199142 /lib/i386-linux-gnu/ld-2.15.so 
b7724000-b7725000 r--p 0001f000 08:01 4199142 /lib/i386-linux-gnu/ld-2.15.so 
b7725000-b7726000 rw-p 00020000 08:01 4199142 /lib/i386-linux-gnu/ld-2.15.so 
bfb5a000-bfb7b000 rw-p 00000000 00:00 0   [stack] 
Aborted (core dumped) 

幫助，將不勝感激。

Answer 1

問題是，你想取消一個不存在的指針。

你想取消指針inputs(-1)%obj這顯然不存在，因爲你沒有分配(-1)st輸入元素。