Type mismatch warning

The following is my code that is supposed to act as a replacement shell for Linux:

Code:

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#include "g5shell.h"

/* Program buffers and work pointers */
static char inpbuf[MAXBUF], tokbuf[2*MAXBUF], *ptr = inpbuf, *tok = tokbuf;

/* ---- USERIN: Print prompt and read a line ---- */
int userin(char *p)
{
    int c, count;
    ptr = inpbuf;
    tok = tokbuf;
   
    printf("%s", p);                                        // Display prompt
   
    count =0;
   
    while(1){
        if ((c = getchar()) == EOF) return(EOF);
        if (count < MAXBUF) inpbuf[count++] = c;
        if (c == '\n' && count < MAXBUF){
            inpbuf[count] = '\0';
            return count;}
        if (c == '\n'){                                    // Restart if line too long
            printf("G5-Shell Error: Input line too long.\n");
            count = 0;
            printf("%s", p);}
    }
}

/* ---- GETTOK: Get token and place into tokbuf ---- */
int gettok(char **outptr)
{
    int type;
   
    *outptr = tok;                                          // Set the outptr string to tok
    while(*ptr == ' ' || *ptr == '\t') ptr++;              // Strip white space from the buffer containing the tokens
    *tok++ = *ptr;                                          // Set token pointer to the 1st token in the buffer
    switch(*ptr++){                                        // Set the type variable depending
        case '\n':                                          // on the token in the buffer
                type = EOL;
                break;
        case '&':
                type = AMPERSAND;
                break;
        case ';':
                type = SEMICOLON;
                break;
        default:
                type = ARG;
                while(inarg(*ptr))                          // Keep reading valid ordinary chars
                    *tok++ = *ptr++;
    }
   
    *tok++ = '\0';
    return type;
}

/* List of special chars for inarg() */
static char special [] = {' ','\t','&',';','\n','\0'};
/* ---- INARG: Check for special chars ---- */
int inarg(char c)
{
    char *wrk;
   
    for(wrk=special; *wrk; wrk++){
        if(c == *wrk) return(0);}
    return(1);
}

/* ---- PROCLINE: Process input line ---- */
int procline(void)
{
    char *arg[MAXARG+1];                                    // Pointer array for runcommand
    int toktype;                                            // Type of token in command
    int narg;                                              // Number of args so far
    int type;                                              // FOREGROUND or BACKGROUND
   
    narg = 0;
   
    for(;;){                                                // Infinite loop
        switch(toktype=gettok(&arg[narg])){                // Take action according to token types
            case ARG:      if(narg<MAXARG) narg++;
                            break;
            case EOL:
            case SEMICOLON:
            case AMPERSAND: if(toktype == AMPERSAND) type = BACKGROUND;
                            else type = FOREGROUND;
                            if(narg != 0){
                                arg[narg] = NULL;
                                runcommand(arg, type);}
                            if(toktype == EOL) return;

                            narg = 0;
                            break;
        }
    }
}

/* ---- RUNCOMMAND: Execute command with optional wait ---- */
int runcommand(char **cline, int where)
{
    pid_t pid;
    int status;
   
    switch(pid = fork()){
        case -1:    perror("G5-Shell");
                    return(-1);
        case 0:    execvp(*cline, cline);
                    perror(*cline);
                    exit(1);
    }
   
    if(where == BACKGROUND){                                // If BACKGROUND process, then print pid and exit
        printf("[Process id %d]\n", pid);
        return(0);}
    if(waitpid(pid, &status, 0) == -1) return;              // Wait until process pid exits
    else return(status);
}

/* Prompt */
char *prompt = "Command> ";

/* ---- MAIN: Main function ---- */
main()
{
    char cmd;
   
    execl("/bin/clear", "clear", (char *)0);                // clear screen
    printf("Welcome to Group 5 Shell System.\n");
   
    while(userin(prompt) != EOF) procline();
}

---

After trying to compile I get the following 2 errors (faulty lines are highlighted on the code):
shell.c:62: warning: type mismatch with previous implicit declaration
shell.c:50: warning: previous implicit declaration of `inarg'

I can't figure out why this is happening. Any help is appreciated.

ptr isn't declared (or initialized) in gettok(), so the compiler has assumed it's an int. Try declaring it as a char * (and initializing it!) at the start of gettok() and the compiler warning should go away.

<edit> Declared static global - nasty!!

You need to declare the inarg (for example after static declaration

Code:

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int inarg(char);

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) func or define it before gettok func.

Quote:

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Originally Posted by SKeane

ptr isn't declared (or initialized) in gettok(), so the compiler has assumed it's an int. Try declaring it as a char * (and initializing it!) at the start of gettok() and the compiler warning should go away.

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Its declared as static.

You didn't prototype (or define) inarg before you've started using it.


Quzah.

Thanks all. Problem solved.