CODEWITHSUNDEEP
cruntime-errorstrcpy
Nir
Nir

Reputation: 175

runtime-error "access violation writing location " with strcpy function

i have this run time error "access violation writing location " with strcpy function

Here part of my code:

else if (strcmp(sentenceRecv, "405002") == 0){
    /*winVersion[SIZE] = (char*)malloc(sizeof(tempString));*/
    system("ver >> text.txt");
    FILE *pfile = fopen("text.txt", "rt+");
    if (pfile == NULL)
    {
        printf("Couldn't open file\n");
    }
    fread(tempString, sizeof(char), SIZE - 1, pfile);
    fclose(pfile);
    pfile = fopen("text.txt", "w");
    if (pfile == NULL)
    {
        printf("Couldn't open file\n");
    }
    fputc((int)' ', pfile);
    fclose(pfile);
    /*  winVersion[SIZE] = strdup(tempString);*/
    strcpy(winVersion, tempString);
    send(ClientSocket, winVersion, sizeof(winVersion), 0);
    menuCheck = 1;
}

The error is in this line:strcpy(winVersion, tempString); and in the first lines i write:

char winVersion[SIZE];
char tempString[SIZE];

Upvotes: 0

Views: 932

Answers (1)

Asics
Asics

Reputation: 868

char tempString[SIZE] = {0};

strcpy() needs a null-terminated string ('\0')

Otherwise it will just keep going until it hits a '\0' somewhere in the contiguous memory which may not belong to your program hence the access violation error.

You could use char *strncpy(char *dest, char *src, size_t n); and specify SIZE as the n number of bytes to copy. This is still somewhat unsafe because the copied strings won't be null-terminated either and could cause more problems later.

http://beej.us/guide/bgc/output/html/multipage/strcpy.html

Upvotes: 2

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