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copying part of the char array to a string in c

I have read many suggested questions, but still cannot find out the answer. I know the content in buffer is a NULL terminated char array, and I want to copy it into a dynamic allocated char array. However, I kept getting segmentation fault from the strcpy function. Thanks for any help.

void myFunction()
{
    char buffer[200];

    // buffer was filled by recvfrom correctly, and can be printed out with printf()
    char *message = malloc(200);

    strcpy(message, buffer[1]);
}

////////////////

ok, so i tried strcpy(message, &buffer[1]); strcpy(message, buffer); but not开发者_JAVA技巧hing worked!!


This works for me. Is it possible that your buffer is not null-terminated?

char buffer[200];
buffer[0] = 'h';
buffer[1] = 'e';
buffer[2] = 'l';
buffer[3] = 'l';
buffer[4] = 'o';
buffer[5] = '\0';

// buffer was filled by recvfrom correctly, and can be printed out with printf()
char *message = (char *)malloc(200);
strcpy(message, buffer);


Your invocation of strcpy(3) is incorrect. Change it to the following:

    buffer[199] = '\0';
    strcpy(message, &buffer[1]);

strcpy(3) has the following signature:

 char *
 stpcpy(char *s1, const char *s2);

You passed in:

 char *stpcpy(char *s1, const char s2); /* won't work */

I would suggest using memcpy(3) instead of strcpy(3) since strcpy(3) relies on a null character to terminate the string.

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