I am writing a program in C that contains two source files, one containing main() and one containing function definitions. I also have a header file declaring the functions and variables so I don't have to pass variables back and forth. Here is the content of the files.
main.c:
#include <stdio.h>
#include "defs.h"
#include "sorting.c"
int main(int argc, char **argv){
listLength = 0;/*this is a load of barnacles*/
EOFFlag = 1;
input = fopen(argv[1], "r");
if(input == NULL){
printf("Could not open requested file.\n");
return -1;
}
while(EOFFlag){
sortNextWord();
}
if(FULLLISTCONSEQUENCES){
for(genericIterator = 0; genericIterator < USHRT_MAX + 1; genericIterator++){
printf("%d: %s; %d", genericIterator + 1, wordlist[genericIterator], wordcount[genericIterator]);
}
}else{
for(genericIterator = 0; genericIterator < listLength; genericIterator++){
printf("%d: %s; %d", genericIterator + 1, wordlist[genericIterator], wordcount[genericIterator]);
}
}
return 1;
}
sorting.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "defs.h"
int sortNextWord(){
getNextWord();
if(wordHolder[0] != '\0')/*checks to ensure that getNextWord didn't get an empty string*/
listMatch();
return 1;
}
int getNextWord(){
char charStore;
char returnFlag = 0;
genericIterator = 0;
while(genericIterator != USHRT_MAX){
switch(charStore = getc(input)){
case EOF:
EOFFlag = 0;
goto exitcond;/* checks for EOF or whitespace, exits loop if found*/
case ' ':
case '\n':
case '\t':
goto exitcond;
default:
wordHolder[genericIterator++] = charStore;/* otherwise it writes the character it read to the next available spot */
break;
}
}
exitcond:
wordHolder[genericIterator] = '\0';
wordlen = genericIterator;
return 1;
}
int listMatch(){/* runs through wordlist to find a matching word. If found, increments the respective wordcount entry, otherwise, creates new entry in wordlist */
for(genericIterator = 0; genericIterator < listLength; genericIterator++){
if(strcmp(wordHolder, wordlist[genericIterator])){
++wordcount[genericIterator];
goto foundmatch;
}
}
addToList();
foundmatch:
return 1;
}
int addToList(){ /*adds word to next available spot in wordlist*/
char *string;
if(FULLLISTCONSEQUENCES) /*doesnt do anything if wordlist is full */
return 0; /* John Freeman, who was Go */
if(listLength == USHRT_MAX)
FULLLISTCONSEQUENCES = 1;
string = malloc((wordlen + 1) * sizeof(char));
string[0] = '\0';
strncat(string, wordHolder, USHRT_MAX + 1);
wordcount[listLength] = 1;
wordlist[listLength++] = string;
return 1;`
}
defs.h (ignore the stuff about heapsort. I'm going to implement that to sort the wordlist, but i need to make sure this works first.
#ifndef DEFS_H
#define DEFS_H
#include <limits.h>
#include <stdio.h>
char *wordlist[USHRT_MAX + 1];
int wordcount [USHRT_MAX + 1];
unsigned short listLength;
unsigned short genericIterator;
FILE *input;
/*heapsort goes here */
char wordHolder[USHRT_MAX + 1];
unsigned short wordlen;
char EOFFlag;
char FULLLISTCONSEQUENCES;
int heapsort();
int buildMaxHeap();
int restoreMaxHeap();
int swap(unsigned short, unsigned short);
unsigned short getParent(unsigned short);
unsigned short getRightChild(unsigned short);
unsigned short getLeftChild(unsigned short);
int sortNextWord();
int getNextWord();
int listMatch();
int addToList();
#endif`
When I run those through gcc with the command
gcc -o wordsort main.c sorting.c
I get the following error:
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0x0): multiple definition of `wordlist'; /tmp/cc3dFw3Q.o:(.bss+0x0): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0x80000): multiple definition of `wordcount'; /tmp/cc3dFw3Q.o:(.bss+0x80000): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xc0000): multiple definition of `listLength'; /tmp/cc3dFw3Q.o:(.bss+0xc0000): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xc0002): multiple definition of `genericIterator'; /tmp/cc3dFw3Q.o:(.bss+0xc0002): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xc0008): multiple definition of `input'; /tmp/cc3dFw3Q.o:(.bss+0xc0008): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xc0020): multiple definition of `wordHolder'; /tmp/cc3dFw3Q.o:(.bss+0xc0020): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xd0020): multiple definition of `wordlen'; /tmp/cc3dFw3Q.o:(.bss+0xd0020): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xd0022): multiple definition of `EOFFlag'; /tmp/cc3dFw3Q.o:(.bss+0xd0022): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o:(.bss+0xd0023): multiple definition of `FULLLISTCONSEQUENCES'; /tmp/cc3dFw3Q.o:(.bss+0xd0023): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o: in function `sortNextWord':
main.c:(.text+0x0): multiple definition of `sortNextWord'; /tmp/cc3dFw3Q.o:sorting.c:(.text+0x0): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o: in function `getNextWord':
main.c:(.text+0x2a): multiple definition of `getNextWord'; /tmp/cc3dFw3Q.o:sorting.c:(.text+0x2a): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o: in function `listMatch':
main.c:(.text+0xdf): multiple definition of `listMatch'; /tmp/cc3dFw3Q.o:sorting.c:(.text+0xdf): first defined here
/usr/bin/ld: /tmp/cc8X0W8R.o: in function `addToList':
main.c:(.text+0x191): multiple definition of `addToList'; /tmp/cc3dFw3Q.o:sorting.c:(.text+0x191): first defined here
collect2: error: ld returned 1 exit status
What is happening? I've only defined these functions once in sorting.c. Where did this error come from?
I've tried removing some of the #include headers, and I added the #ifndef statement to defs.h. Neither made any difference. I've also tried compiling and then linking as suggested in https://stackoverflow.com/questions/18777326/compiling-multiple-c-files-with-gcc`your text`
