Multiple definition [...] first define here
Solution 1
You must keep only the declarations in a .h file, not the definitions, lest you should get any linker errors. These
int I_Macroblock_Modes[27][7];
int P_and_SP_macroblock_modes[32][7];
int B_Macroblock_Modes[50][7];
are definitions, not intuitive as it may seem. Change these to
extern int I_Macroblock_Modes[27][7];
extern int P_and_SP_macroblock_modes[32][7];
extern int B_Macroblock_Modes[50][7];
and you should be fine
Solution 2
It's not "just defines". You are declaring variables inside it, therefore every time that gets included your are redeclaring global variables.
If what you want is to access I_Macroblock_Modes
from other .c/.cpp files, in the macroblocktables.h header you should put:
//resides in macroblocktables.cpp
extern int I_Macroblock_Modes[27][7];
extern int P_and_SP_macroblock_modes[32][7];
extern int B_Macroblock_Modes[50][7];
// the rest of it
Because those int arrays are defined in macroblocktables.cpp, right?
In C/C++ everytime you do something like:
int myarray[4];
char mychar;
or more generally
type var_name;
you are telling to the compiler: please allocate on the stack for me, a variable named X
that has type T
.
when you #include header.h
, in the most basic explanation, you are telling the preprocessor: open header.h ctrl+c all of it, and ctrl+v it here. Then that preprocessed source file is fed to your compiler and every time it sees type var_name
it will do what i explained above.
Sorry if this is too much info, but I just felt like writing it :P
Pedro Dusso
I am interested in database systems, artificial intelligence, and big data processing to support data-intensive science. I have worked as research assistant with distributed monitoring systems, federated cloud services, and traceability of engineering requirements. As intern, I have worked with Intranet web portals, documentation, and mobile.
Updated on June 23, 2020Comments
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Pedro Dusso almost 4 years
I'm writing a H264 parser (no OO), but I'm trying to use some modules to organize better the things.
I'm having this problems:
`CMakeFiles/server.dir/mainclass.cpp.o:(.bss+0x0): multiple definition of `I_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x0): first defined here `CMakeFiles/server.dir/mainclass.cpp.o:(.bss+0x300): multiple definition of `P_and_SP_macroblock_modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x300): first defined here `CMakeFiles/server.dir/mainclass.cpp.o:(.bss+0x680): multiple definition of `B_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x680): first defined here `CMakeFiles/server.dir/thRunAppl.cpp.o:(.bss+0x0): multiple definition of `I_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x0): first defined here `CMakeFiles/server.dir/thRunAppl.cpp.o:(.bss+0x300): multiple definition of `P_and_SP_macroblock_modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x300): first defined here `CMakeFiles/server.dir/thRunAppl.cpp.o:(.bss+0x680): multiple definition of `B_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x680): first defined here `CMakeFiles/server.dir/h.264parser.cpp.o:(.bss+0x0): multiple definition of `I_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x0): first defined here `CMakeFiles/server.dir/h.264parser.cpp.o:(.bss+0x300): multiple definition of `P_and_SP_macroblock_modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x300): first defined here `CMakeFiles/server.dir/h.264parser.cpp.o:(.bss+0x680): multiple definition of `B_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x680): first defined here `CMakeFiles/server.dir/moc_mainclass.cxx.o:(.bss+0x0): multiple definition of `I_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x0): first defined here `CMakeFiles/server.dir/moc_mainclass.cxx.o:(.bss+0x300): multiple definition of `P_and_SP_macroblock_modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x300): first defined here `CMakeFiles/server.dir/moc_mainclass.cxx.o:(.bss+0x680): multiple definition of `B_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x680): first defined here `CMakeFiles/server.dir/moc_thRunAppl.cxx.o:(.bss+0x0): multiple definition of `I_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x0): first defined here `CMakeFiles/server.dir/moc_thRunAppl.cxx.o:(.bss+0x300): multiple definition of `P_and_SP_macroblock_modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x300): first defined here `CMakeFiles/server.dir/moc_thRunAppl.cxx.o:(.bss+0x680): multiple definition of `B_Macroblock_Modes' `CMakeFiles/server.dir/main.cpp.o:(.bss+0x680): first defined here `CMakeFiles/server.dir/h.264parser.cpp.o: In function `MbPartPredMode(int, int)': `h.264parser.cpp:(.text+0xf0): undefined reference to `B_macroblockmodes(int, int)' `h.264parser.cpp:(.text+0x104): undefined reference to `B_macroblockmodes(int, int)' `h.264parser.cpp:(.text+0x111): undefined reference to `I_macroblockmodes(int, int)' `h.264parser.cpp:(.text+0x124): undefined reference to `P_and_SP_macroblockmodes(int, int)' `h.264parser.cpp:(.text+0x134): undefined reference to `P_and_SP_macroblockmodes(int, int)'
My scenario is:
macroblocktypes.h. just with defines
macroblocktables.h:
#include "macroblocktypes.h" int I_Macroblock_Modes[27][7]; int P_and_SP_macroblock_modes[32][7]; int B_Macroblock_Modes[50][7]; int I_macroblockmodes(int line, int column); int P_and_SP_macroblockmodes(int line, int column); int B_macroblockmodes(int line, int column);
macroblocktables.cpp, with a array and a function defined like this for each array and function on .h file.
#include "macroblocktables.h" int I_macroblock_modes[27][7] ={ {0, I_4x4, 0, Intra_4x4, NA, NA, NA}, //If this line was to be commented out, the MbPartPredMode macro would have to be changed //since it relies on the linear rise of the value in the first column. //{0, I_NxN, 1, Intra_8x8, NA, NA, NA}, {1, I_16x16_0_0_0, NA, Intra_16x16, 0, 0, 0}, {2, I_16x16_1_0_0, NA, Intra_16x16, 1, 0, 0}, {3, I_16x16_2_0_0, NA, Intra_16x16, 2, 0, 0}, {4, I_16x16_3_0_0, NA, Intra_16x16, 3, 0, 0}, {5, I_16x16_0_1_0, NA, Intra_16x16, 0, 1, 0}, {6, I_16x16_1_1_0, NA, Intra_16x16, 1, 1, 0}, {7, I_16x16_2_1_0, NA, Intra_16x16, 2, 1, 0}, {8, I_16x16_3_1_0, NA, Intra_16x16, 3, 1, 0}, {9, I_16x16_0_2_0, NA, Intra_16x16, 0, 2, 0}, {10, I_16x16_1_2_0, NA, Intra_16x16, 1, 2, 0}, {11, I_16x16_2_2_0, NA, Intra_16x16, 2, 2, 0}, {12, I_16x16_3_2_0, NA, Intra_16x16, 3, 2, 0}, {13, I_16x16_0_0_1, NA, Intra_16x16, 0, 0, 15}, {14, I_16x16_1_0_1, NA, Intra_16x16, 1, 0, 15}, {15, I_16x16_2_0_1, NA, Intra_16x16, 2, 0, 15}, {16, I_16x16_3_0_1, NA, Intra_16x16, 3, 0, 15}, {17, I_16x16_0_1_1, NA, Intra_16x16, 0, 1, 15}, {18, I_16x16_1_1_1, NA, Intra_16x16, 1, 1, 15}, {19, I_16x16_2_1_1, NA, Intra_16x16, 2, 1, 15}, {20, I_16x16_3_1_1, NA, Intra_16x16, 3, 1, 15}, {21, I_16x16_0_2_1, NA, Intra_16x16, 0, 2, 15}, {22, I_16x16_1_2_1, NA, Intra_16x16, 1, 2, 15}, {23, I_16x16_2_2_1, NA, Intra_16x16, 2, 2, 15}, {24, I_16x16_3_2_1, NA, Intra_16x16, 3, 2, 15}, {25, I_PCM, NA, NA, NA, NA, NA}}; int P_and_SP_macroblock_modes[32][7] = { {0, P_L0_16x16, 1, Pred_L0, NA, 16, 16}, {1, P_L0_L0_16x8, 2, Pred_L0, Pred_L0, 16, 8}, {2, P_L0_L0_8x16, 2, Pred_L0, Pred_L0, 8, 16}, {3, P_8x8, 4, NA, NA, 8, 8}, {4, P_8x8ref0, 4, NA, NA, 8, 8}, {0, I_4x4, 0, Intra_4x4, NA, NA, NA}, {1, I_16x16_0_0_0, NA, Intra_16x16, 0, 0, 0}, {2, I_16x16_1_0_0, NA, Intra_16x16, 1, 0, 0}, {3, I_16x16_2_0_0, NA, Intra_16x16, 2, 0, 0}, {4, I_16x16_3_0_0, NA, Intra_16x16, 3, 0, 0}, {5, I_16x16_0_1_0, NA, Intra_16x16, 0, 1, 0}, {6, I_16x16_1_1_0, NA, Intra_16x16, 1, 1, 0}, {7, I_16x16_2_1_0, NA, Intra_16x16, 2, 1, 0}, {8, I_16x16_3_1_0, NA, Intra_16x16, 3, 1, 0}, {9, I_16x16_0_2_0, NA, Intra_16x16, 0, 2, 0}, {10, I_16x16_1_2_0, NA, Intra_16x16, 1, 2, 0}, {11, I_16x16_2_2_0, NA, Intra_16x16, 2, 2, 0}, {12, I_16x16_3_2_0, NA, Intra_16x16, 3, 2, 0}, {13, I_16x16_0_0_1, NA, Intra_16x16, 0, 0, 15}, {14, I_16x16_1_0_1, NA, Intra_16x16, 1, 0, 15}, {15, I_16x16_2_0_1, NA, Intra_16x16, 2, 0, 15}, {16, I_16x16_3_0_1, NA, Intra_16x16, 3, 0, 15}, {17, I_16x16_0_1_1, NA, Intra_16x16, 0, 1, 15}, {18, I_16x16_1_1_1, NA, Intra_16x16, 1, 1, 15}, {19, I_16x16_2_1_1, NA, Intra_16x16, 2, 1, 15}, {20, I_16x16_3_1_1, NA, Intra_16x16, 3, 1, 15}, {21, I_16x16_0_2_1, NA, Intra_16x16, 0, 2, 15}, {22, I_16x16_1_2_1, NA, Intra_16x16, 1, 2, 15}, {23, I_16x16_2_2_1, NA, Intra_16x16, 2, 2, 15}, {24, I_16x16_3_2_1, NA, Intra_16x16, 3, 2, 15}, {25, I_PCM, NA, NA, NA, NA, NA}, {NA, P_Skip, 1, Pred_L0, NA, 16, 16}}; int B_macroblock_modes[50][7] = { {0, B_Direct_16x16, NA, Direct, NA, 8, 8}, {1, B_L0_16x16, 1, Pred_L0, NA, 16, 16}, {2, B_L1_16x16, 1, Pred_L1, NA, 16, 16}, {3, B_Bi_16x16, 1, BiPred, NA, 16, 16}, {4, B_L0_L0_16x8, 2, Pred_L0, Pred_L0, 16, 8}, {5, B_L0_L0_8x16, 2, Pred_L0, Pred_L0, 8, 16}, {6, B_L1_L1_16x8, 2, Pred_L1, Pred_L1, 16, 8}, {7, B_L1_L1_8x16, 2, Pred_L1, Pred_L1, 8, 16}, {8, B_L0_L1_16x8, 2, Pred_L0, Pred_L1, 16, 8}, {9, B_L0_L1_8x16, 2, Pred_L0, Pred_L1, 8, 16}, {10, B_L1_L0_16x8, 2, Pred_L1, Pred_L0, 16, 8}, {11, B_L1_L0_8x16, 2, Pred_L1, Pred_L0, 8, 16}, {12, B_L0_Bi_16x8, 2, Pred_L0, BiPred, 16, 8}, {13, B_L0_Bi_8x16, 2, Pred_L0, BiPred, 8, 16}, {14, B_L1_Bi_16x8, 2, Pred_L1, BiPred, 16, 8}, {15, B_L1_Bi_8x16, 2, Pred_L1, BiPred, 8, 16}, {16, B_Bi_L0_16x8, 2, BiPred, Pred_L0, 16, 8}, {17, B_Bi_L0_8x16, 2, BiPred, Pred_L0, 8, 16}, {18, B_Bi_L1_16x8, 2, BiPred, Pred_L1, 16, 8}, {19, B_Bi_L1_8x16, 2, BiPred, Pred_L1, 8, 16}, {20, B_Bi_Bi_16x8, 2, BiPred, BiPred, 16, 8}, {21, B_Bi_Bi_8x16, 2, BiPred, BiPred, 8, 16}, {22, B_8x8, 4, NA, NA, 8, 8}, {0, I_4x4, 0, Intra_4x4, NA, NA, NA}, {1, I_16x16_0_0_0, NA, Intra_16x16, 0, 0, 0}, {2, I_16x16_1_0_0, NA, Intra_16x16, 1, 0, 0}, {3, I_16x16_2_0_0, NA, Intra_16x16, 2, 0, 0}, {4, I_16x16_3_0_0, NA, Intra_16x16, 3, 0, 0}, {5, I_16x16_0_1_0, NA, Intra_16x16, 0, 1, 0}, {6, I_16x16_1_1_0, NA, Intra_16x16, 1, 1, 0}, {7, I_16x16_2_1_0, NA, Intra_16x16, 2, 1, 0}, {8, I_16x16_3_1_0, NA, Intra_16x16, 3, 1, 0}, {9, I_16x16_0_2_0, NA, Intra_16x16, 0, 2, 0}, {10, I_16x16_1_2_0, NA, Intra_16x16, 1, 2, 0}, {11, I_16x16_2_2_0, NA, Intra_16x16, 2, 2, 0}, {12, I_16x16_3_2_0, NA, Intra_16x16, 3, 2, 0}, {13, I_16x16_0_0_1, NA, Intra_16x16, 0, 0, 15}, {14, I_16x16_1_0_1, NA, Intra_16x16, 1, 0, 15}, {15, I_16x16_2_0_1, NA, Intra_16x16, 2, 0, 15}, {16, I_16x16_3_0_1, NA, Intra_16x16, 3, 0, 15}, {17, I_16x16_0_1_1, NA, Intra_16x16, 0, 1, 15}, {18, I_16x16_1_1_1, NA, Intra_16x16, 1, 1, 15}, {19, I_16x16_2_1_1, NA, Intra_16x16, 2, 1, 15}, {20, I_16x16_3_1_1, NA, Intra_16x16, 3, 1, 15}, {21, I_16x16_0_2_1, NA, Intra_16x16, 0, 2, 15}, {22, I_16x16_1_2_1, NA, Intra_16x16, 1, 2, 15}, {23, I_16x16_2_2_1, NA, Intra_16x16, 2, 2, 15}, {24, I_16x16_3_2_1, NA, Intra_16x16, 3, 2, 15}, {25, I_PCM, NA, NA, NA, NA, NA}, {NA, B_Skip, NA, Direct, NA, 8, 8}}; int I_macroblockmodes(int line, int column) { if (line < 27 && column < 7) return I_macroblock_modes[line][column]; else { if (line >= 27) { return -10000; //line is bigger than the array size } else { return -20000; //column is bigger than the array size } }} //Inter prediction slices - Macroblock types //Defined strictly by norm, page 121. //(Table 7-13 Macroblock type values 0 to 4 for P and SP slices) /* First column: mb_type Second column: Name of mb_type Third column: NumMbPart( mb_type ) Fourth column: MbPartPredMode( mb_type, 0 ) Fifth column: MbPartPredMode( mb_type, 1 ) Sixth column: MbPartWidth( mb_type ) Seventh column: MbPartHeight( mb_type ) */ int P_and_SP_macroblockmodes(int line, int column){ if (line < 32 && column < 7) return P_and_SP_macroblock_modes[line][column]; else { if (line >= 32) { return -10000; //line is bigger than the array size } else { return -20000; //column is bigger than the array size } }} //p94. Table 7-14 – Macroblock type values 0 to 22 for B slices /* First column: mb_type Second column: Name of mb_type Third column: NumMbPart( mb_type ) Fourth column: MbPartPredMode( mb_type, 0 ) Fifth column: MbPartPredMode( mb_type, 1 ) Sixth column: MbPartWidth( mb_type ) Seventh column: MbPartHeight( mb_type ) */ int B_macroblockmodes(int line, int column){ if (line < 50 && column < 7) return B_macroblock_modes[line][column]; else { if (line >= 50) { return -10000; //line is bigger than the array size } else { return -20000; //column is bigger than the array size } }}
And finally my h.264 files (.cpp and .h). Im including in the .h the macroblocktable.h and macroblocktype.h, and in the h.264.cpp just the h.264.h.
I would like to use the functions from the macroblocktable.cpp in the h.264.cpp.
Thanks in advance
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Pedro Dusso almost 13 yearsSorry dont make it clear, but the file with just defines is the macroblocktypes.h. I know the macroblocktable.h have variables declared on it
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Pedro Dusso almost 13 yearsThanks for your answer but I dont wanna access the arrays outside, but kind of encapsulate then in the macroblocktable.cpp and call the functions from that .cpp. I remove the declarations from the .h, and the 'multiple definition' errors stop; but i still having the 'h.264parser.cpp:(.text+0x104): undefined reference to `B_macroblockmodes(int, int)'' error when I try to call the functions from the h.265.cpp. =(
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Armen Tsirunyan almost 13 years@Pmdusso: You don't need to remove any declarations from anywhere. Follow these steps: 1) In the .h file add the
extern
keyword to the array declarations. Leave the array definitions in the cpp file intact. 2) Add the definition ofB_macroblockmodes(int, int)
function to the cpp file (you have forgotten to write the body, hence the error) -
Pedro Dusso almost 13 yearsif you mean write the B_macroblockmodes(int, int) in the macroblocktable.cpp, I did! You can see in the question... and I write the definitions of the arrays back in the macroblocktable.h with the extern, thanks!
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Armen Tsirunyan almost 13 years@Pmdusso: er... no, you haven't. Where is the body of that function?
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Pedro Dusso almost 13 yearsah... sorry... I just wrote the int I_macroblockmodes(int line, int column) to save space here... but all three are there, I will edit it. Thats it, they are there now.
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Pedro Dusso almost 13 years@hexa should i make the functions extern also? Making the arrays extern resolved the multiple definition... but i dont know what to do with the functions now!
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Vinicius Kamakura almost 13 yearsthe function prototypes are fine :) en.wikipedia.org/wiki/Function_prototype
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Pedro Dusso almost 13 yearsyep they are but still having 'undefined reference to' error from the h.264.cpp... =/
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Vinicius Kamakura almost 13 yearsare you including the .h on h264.cpp? with the added
extern
for the arrays?