C++ Compile Error in Linux

Question

Below is my code which compiles fine on eclipse. It is fully functional, just a basic program that prints memory addresses.

#include <stdio.h>
#include <stdlib.h>

int g0;       /* global variable, uninitialized */
int g1 = 14;  /* global variable, initialized */
int g2[1000]; /* global variable, uninitialized */
int g3 = 16;  /* global variable, initialized */
int g4;       /* global variable, uninitialized */

void proc1();
void proc2();

int main()
{
    extern int etext[], edata[], end[];

    int lc0;      /* local variable, stored on stack */
    int lc1 = 27; /* local variable, stored on stack; mix init and uninit */
    int lc2;      /* local variable, stored on stack */
        static int ls0; /* local static variable, uninitialized data */
        static int ls1 = 19;      /* local static variable, initialized data */
        int *pheap1;
        int *pheap2;

        pheap1 = (int *) malloc(sizeof(int));
        pheap2 = (int *) malloc(sizeof(int));

        printf("\n\n---------- main -------------------\n\n");
        printf("%8p (%10lu): Last address\n",
        0xffffffff, 0xffffffff);

        printf("%8p (%10lu): Address etext\n",
        etext, etext);
        printf("%8p (%10lu): Address edata\n",
        edata, edata);
        printf("%8p (%10lu): Address end\n",
        end, end);

        printf("%8p (%10lu): Address of code for proc1\n",
        &proc1, &proc1);
        printf("%8p (%10lu): Address of code for proc2\n",
        &proc2, &proc2);

        printf("%8p (%10lu): Address of uninitialized global variable g0\n",
        &g0, &g0);
        printf("%8p (%10lu): Address of initialized   global variable g1\n",
        &g1, &g1);
        printf("%8p (%10lu): Address of uninitialized global array    g2\n",
        &g2[0], &g2[0]);
        printf("%8p (%10lu): Address of initialized   global variable g3\n",
        &g3, &g3);
        printf("%8p (%10lu): Address of uninitialized global variable g4\n",
        &g4, &g4);

        printf("%8p (%10lu): Address heap1 in heap space\n",
        pheap1, (int) pheap1);
        printf("%8p (%10lu): Address heap2 in heap space\n",
        pheap2, (int) pheap2);

    printf("%8p (%10lu): Address of local variable lc0\n",
        &lc0, &lc0);
    printf("%8p (%10lu): Address of local variable lc1\n",
        &lc1, &lc1);
    printf("%8p (%10lu): Address of local variable lc2\n",
        &lc2, &lc2);

    printf("%8p (%10lu): Address of local uninitialized static var ls0\n",
        &ls0, &ls0);
    printf("%8p (%10lu): Address of local initialized   static var ls1\n",
        &ls1, &ls1);

    proc1();
    proc2();

    return 0;
}
void proc1() {
    int lc3;
    int lc4 = 37;

    printf("\n\n----------- proc1 ------------------\n\n");
    printf("%8p (%10lu): Address of code for proc1\n",
        &proc1, &proc1);
    printf("%8p (%10lu): Address of global variable g0\n",
        &g0, &g0);
    printf("%8p (%10lu): Address of global variable g1\n",
        &g1, &g1);
    printf("%8p (%10lu): Address of global variable g2\n",
        &g2[0], &g2[0]);
    printf("%8p (%10lu): Address of global variable g3\n",
        &g3, &g3);
    printf("%8p (%10lu): Address of global variable g4\n",
        &g4, &g4);
    printf("%8p (%10lu): Address of local variable lc3\n",
        &lc3, &lc3);
    printf("%8p (%10lu): Address of local variable lc4\n",
        &lc4, &lc4);
}

void proc2() {
    int lc5;
    int lc6 = 51;
    static int ls2;
    static int ls3 = 47;

    printf("\n\n------------ proc2 -----------------\n\n");
    printf("%8p (%10lu): Address of code for proc2\n",
        &proc2, &proc2);
    printf("%8p (%10lu): Address of global variable g0\n",
        &g0, &g0);
    printf("%8p (%10lu): Address of global variable g1\n",
        &g1, &g1);
    printf("%8p (%10lu): Address of global variable g2\n",
        &g2[0], &g2[0]);
    printf("%8p (%10lu): Address of global variable g3\n",
        &g3, &g3);
    printf("%8p (%10lu): Address of global variable g4\n",
        &g4, &g4);
    printf("%8p (%10lu): Address of local variable lc5\n",
        &lc5, &lc5);
    printf("%8p (%10lu): Address of local variable lc6\n",
        &lc6, &lc6);
    printf("%8p (%10lu): Address of local uninitialized static var ls2\n",
        &ls2, &ls2);
    printf("%8p (%10lu): Address of local initialized   static var ls3\n",
        &ls3, &ls3);
}

however when I tried to manually compile it:

gcc memory_segments.cpp

i get tons of errors:

U91:~/Documents/workspace/memory_segments$ gcc memory_segments.cpp
memory_segments.cpp: In function ‘int main()’:
memory_segments.cpp:97: warning: format ‘%8p’ expects type ‘void*’, but argument 2 has type ‘unsigned int’
memory_segments.cpp:97: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘unsigned int’
memory_segments.cpp:100: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:102: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:104: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:107: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:109: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:112: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:114: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:116: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:118: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:120: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:123: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int’
memory_segments.cpp:125: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int’
memory_segments.cpp:128: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:130: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:132: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:135: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:137: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp: In function ‘void proc1()’:
memory_segments.cpp:150: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:152: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:154: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:156: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:158: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:160: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:162: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:164: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp: In function ‘void proc2()’:
memory_segments.cpp:175: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:177: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:179: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:181: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:183: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:185: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:187: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:189: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:191: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:193: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
/tmp/ccRXp46P.o:(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status
devon@D3V-U91:~/Documents/workspace/memory_segments$ gcc memory_segments.cpp -lpthread
memory_segments.cpp: In function ‘int main()’:
memory_segments.cpp:97: warning: format ‘%8p’ expects type ‘void*’, but argument 2 has type ‘unsigned int’
memory_segments.cpp:97: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘unsigned int’
memory_segments.cpp:100: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:102: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:104: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:107: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:109: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:112: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:114: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:116: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:118: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:120: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:123: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int’
memory_segments.cpp:125: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int’
memory_segments.cpp:128: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:130: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:132: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:135: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:137: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp: In function ‘void proc1()’:
memory_segments.cpp:150: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:152: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:154: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:156: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:158: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:160: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:162: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:164: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp: In function ‘void proc2()’:
memory_segments.cpp:175: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘void (*)()’
memory_segments.cpp:177: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:179: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:181: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:183: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:185: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:187: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:189: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:191: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
memory_segments.cpp:193: warning: format ‘%10lu’ expects type ‘long unsigned int’, but argument 3 has type ‘int*’
/tmp/ccJoHGm5.o:(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

Can someone tell me what I'm doing wrong?

no reason to cast your malloc results. compiler does it implicitly. Also you should always check your return value from malloc for negative and exit immediately if there is an error — Stelios Savva, Nov 24 '13 at 14:21
Well you can see that most of the errors are actually warnings which are easily understood and easily fixed (I hope). You're only actual error is a new one to me, but this link might help, http://stackoverflow.com/questions/329059/what-is-gxx-personality-v0-for. — john, Nov 24 '13 at 14:22
You really should type `man printf` and see what exactly is meant by `%10lu`. You are basically assuming a pointer has the same size as a `long unsigned int`. Try `%p` instead. Or just use iostreams. — kccqzy, Nov 24 '13 at 14:23
@Stelios: title and tags say this is C++ (hard to believe though). So the cast is necessary. — Mat, Nov 24 '13 at 14:27

score 2 · Accepted Answer · answered Nov 24 '13 at 14:24

2

The file extension is CPP, so GCC thinks that it is a C++ file. However you're trying to link with GCC, which doesn't know how to link c++ programs. Use g++ for the commandline, or rename the file to a .c file.

answered Nov 24 '13 at 14:24

Ernest Friedman-Hill

80,601
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1

Are you sure? All those warnings will persist, but the actual errors are link errors that should be fixed. – Ernest Friedman-Hill Nov 24 '13 at 14:26
1

what do you mean by link errors? theres only one file, so theres nothing else to link onto... right? – NewFile Nov 24 '13 at 14:27
2

@NewFile: wrong. The only error in what you posted above is a linker (`ld`) error. Doesn't matter that there's only one source file. – Mat Nov 24 '13 at 14:32

score 1 · Answer 2 · answered Nov 24 '13 at 16:55

1

You want to print memory addresses, they are pointers. The printf formatting tokens expect integers. You should cast them to integers, so extend &pointerVariable to (unsigned long int)&pointerVariable.

answered Nov 24 '13 at 16:55

peterh

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C++ Compile Error in Linux

2 Answers2