c pass a string to function then return a string

Question

After exploring the internet, i've wrote the following script, but still got errors, anyone knows what the errors are?( the line with //err)

typedef struct name_value_set {
    char name[250]; 
    char value[250]; 
} nv_set;

char * getInput2(char *param) {
    char *my_data=0;
    int data_len;
    char *tmp_ptr, *tmp;
    int i;
    nv_set *nv;

    data_len=atoi(getenv("CONTENT_LENGTH"));
    char field[data_len]; 

    my_data=(char*)malloc(sizeof(char)*(data_len+1));
    fread(my_data,1,data_len,stdin);

    i=0;
    while (my_data[0]!='\0') {
     tmp=split(my_data,'='); // err
     makespace(tmp); 
     tmp=convert(tmp); // err
     strcpy(nv[i].name,tmp); // 
     tmp=split(my_data,'&'); //err 
     makespace(tmp); // 
     tmp=convert(tmp); // err
     strcpy(nv[i].value,tmp); // 
     i++;
    }
    i--; // 

    int j=0;
    for (j=0; j<i; j++) {
    if(nv[j].name == param) {
        return nv[j].value;
    }


}


void makespace(char *s)
{
    int i,len;
    len=strlen(s);

    for (i=0;i<len;i++) {
      if (s[i]=='+')
        s[i]=' ';
    }
}

char *split(char *s, char stop)
{
    char *data;
    char *tmp;
    int i,len,j;

    len=strlen(s);
    tmp=s;
    data=(char*)malloc(sizeof(char)*(len+1));

    for (i=0;i<len;i++) {
       if (s[i]!=stop)
         data[i]=s[i]; // 
      else {
        i+=1; // 
          break;
       } 
    }
    data[i]='\0';
    for (j=i;j<len;j++)
      s[j-i]=tmp[j];
      s[len-i]='\0';
     return data;
}


char *convert(char *s)
{
    int x,y,len;
    char *data;

    len=strlen(s);
    data=(char*)malloc(sizeof(char)*(len+1));
    y=0;
    for (x=0;x<len;x++) {
    if (s[x]!='%') {
        data[y]=s[x]; // 
          y++;
      }
    else {

        data[y]=(char)(16*hexa(s[x+1])+hexa(s[x+2]));
        y++;
        x=x+2;
      }
    }
     data[y]='\0';
     return data;
}


int hexa(char c)
{
    switch(c) {
    case '0':return 0;
    case '1':return 1;
    case '2':return 2;
    case '3':return 3;
    case '4':return 4;
    case '5':return 5;
    case '6':return 6;
    case '7':return 7;
    case '8':return 8;
    case '9':return 9;
    case 'A':return 10;
    case 'B':return 11;
    case 'C':return 12;
    case 'D':return 13;
    case 'E':return 14;
    case 'F':return 15;
    }
    return 0;
}

You don't say what the error is, but you may just need to forward declare your functions. The compiler parses your file in order and when it's compiling your first function it hasn't "seen" split() yet. So put extern char *split(char *, char); at the top and see if that helps. (repeat for other functions, of course) — Ben Jackson
– Ben Jackson, Commented Nov 1, 2010 at 5:52
Don't be vague, be an ace; write a proper test-case! tinyurl.com/so-hints sscce.org xs4all.nl/~weegen/eelis/iso-c++/testcase.xhtml — Roger Pate
– Roger Pate, Commented Nov 1, 2010 at 5:52
"still got errors" Well, what kind of errors? Are they compiler errors? Does it compile? If so, can you run it? Does it crash? Does it not work correctly? Have you tried attaching a debugger to see what is wrong with it? — James McNellis
– James McNellis, Commented Nov 1, 2010 at 5:52
all errors are "assignment makes pointer from integer without a cast" — friends
– friends, Commented Nov 1, 2010 at 5:54
What is this "script" supposed to do and what errors are you seeing? — Firoze Lafeer
– Firoze Lafeer, Commented Nov 1, 2010 at 5:54

FuriousLuke · Accepted Answer · 2010-11-01 05:53:16Z

1

Try adding prototypes for the functions "makespace", "split", "convert" and "hexa" at the beginning of your code; I expect what you're seeing is the result of implicitly declared functions conflicting with the function definitions. Also, just to be sure, you're including stdio.h and string.h in your source file, right?

answered Nov 1, 2010 at 5:53

FuriousLuke

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2 Comments

friends Over a year ago

i've find out my_data got nothing~ have any ideas? data_len=atoi(getenv("CONTENT_LENGTH")); my_data=(char*)malloc(sizeof(char)*(data_len+1)); fread(my_data,1,data_len,stdin);

FuriousLuke Over a year ago

Okay, "my_data got nothing" is a little ambiguous, and I think it is entirely unrelated to the original question, but let's have at it anyway. I'm going to assume you mean 'my_data' is NULL after the 'malloc'. You may wish to confirm that the environment variable CONTENT_LENGTH is in fact set to a sane value, or even set at all.

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