Mid function in C

Very explicitely show me what it is that you want to do. Right now you have code that will take a string like this:

substr("XX01234567890AB", 2, 3)

That will produce

012

What do you wish for such code to do?

Quote:

---

Originally Posted by sergioms

iPosStart = strrpos (pPacote, cSTX);

---

so what does strrpos() look like and what is cSTX initialized to?

Quote:

---

Originally Posted by sergioms

if(iPosStart >= 0)
iPosStart++;

---

your criteria for finding the start position needs to be reviewed.

Quote:

---

Originally Posted by sergioms

iPosEnd = strrpos (pPacote, cCR);

---

same goes for finding the end position in the string.

now I Change the code, and make a strpos to find begin start char...

Code:

---

int strpos (unsigned char *pStrText, char pChar){        // Última ocorrência do caractere.
       
        int iLen, iCont;
        iLen = strlen (pStrText);

        if (iLen > 0){
                for (iCont=0; iCont<iLen; iCont++){
                        if (pStrText[iCont] ==  pChar)
                                return iCont;
                }
                return 0;        // N&#227;o houve ocorr&#234;ncias
        }
        else { return 0; }        // String Nula
}

---

printCom1 (substr ("XX01234567890AB", 2, 3));
Result: 012

........

Code:

---

#define STX 2
#define CR 13
#define LF 10
#define TAB 9

char cSTX;
char cCR;
char cLF;
char cTab;

        cSTX = STX;
        cCR  = CR;
        cLF  = LF;
        cTab = TAB;


.......

        char cFuncao [2];
        char *cPacote = malloc(pLen);
       
        int iPosStart, iPosEnd, iPosTam;
                       
        //Separa o Pacote
        iPosStart = strpos (pPacote, cSTX);
        iPosStart++;
       
        iPosEnd  = strpos (pPacote, cCR);
       
        iPosTam = iPosEnd - iPosStart;
                               
        if((iPosStart) && (iPosEnd)){
                cPacote = substr(pPacote, iPosStart, iPosTam);
               
                printCom1 ("cPacote: %s\n", cPacote);
                printCom1 ("pPacote: %s\n", pPacote);
                printCom1 ("iPosStart/iPosEnd/iPosTam: %d %d %d",iPosStart, iPosEnd, iPosTam);

---

Result:
cPacote: X34567890AB
pPacote: XX34567890AB
iPosStart/iPosEnd/iPosTam: 1 12 11

The problem is here: if((iPosStart) && (iPosEnd)){

The First Ocurrence at String, is at 0 index

And, because I'm incrementing iPosStart

thanks for all!

?

substr return 0

Because the first occurence of char at string
is 0

Click the link, perhaps.

where ?

The "?" was a link to a page about strstr(). A C Standard Library function that does what your homemade one does.