GDB小试

/*《The C Programming Language》SECTION 5.6 中的一个例子*/
    #include<stdio.h>
    #include<stdlib.h>
    #include<string.h>
    #define MAXLINES 5000        /* max #lines to be sorted */
    char *lineptr[MAXLINES];    /* pointers to text lines */
    int readlines(char *lineptr[], int nlines);
    void writelines(char *lineptr[], int nlines);
    void myqsort(char *lineptr[], int left, int right);
    /* srot input lines */
    int
    main(int argc, int *argv[] )
    {
        printf("Welcome U to have a try!Have a good time!Please press Ctrl+d to finish your input ,starting a new line in Linux environment. And press Ctrl+z in Windows.\n");
        printf("EOF is ???? : %d\nYour input are:\n" , EOF);
        int nlines;                /* number of input lines read */
        if ((nlines = readlines(lineptr, MAXLINES)) >= 0){
            myqsort(lineptr, 0, nlines-1);
            printf("\nSo the result of sorting are:\n\n");
            writelines(lineptr, nlines);
            return 0;
        } else {
            printf("error: input too big to sort \n");
            return -1;
        }
    }
    #define MAXLEN 1000
    int getline(char *, int);
    char *alloc(int);
    /* readlines: read input lines */
    int
    readlines(char *lineptr[], int maxlines)
    {
        int len , nlines;
        char *p , line[MAXLEN];
        nlines = 0;
        while ((len = getline(line, MAXLEN)) > 0)
            if (nlines >= maxlines || (p = malloc(len)) == NULL)
                return -1;
            else {
                line[len-1] = '\0';        /* delete newline */
                strcpy(p, line);
                lineptr[nlines++] = p;
            }
        return nlines;
    }
    /* getline: read a line into s, return length */
    int
    getline(char s[], int lim)
    {
        int c, i;
        for (i=0; i<lim-1 && (c=getchar()) != EOF && c != '\n'; ++i)
            s[i] = c;
        if (c == '\n'){
            s[i] = c;
            ++i;
        }
        s[i] = '\n';
        return i;
    }
    /* writelines: write output lines */
    void
    writelines(char *lineptr[], int nlines)
    {
        while (nlines-- > 0)
            printf("%s\n" , *lineptr++);
    }
    /* myqsort: sort v[left],,,v[right] into increasing order */
    void
    myqsort(char *v[], int left, int right)
    {
        int i ,last;
        void swap(char *v[], int i, int j);
        if (left >= right)        /* do nothing if array contains */
            return;                /* fewer than two elements */
        swap(v, left, (left + right)/2);
        last = left;
        for(i = left + 1; i <= right; i++)
            if (strcmp(v[i], v[left]) < 0)
                swap(v, ++last, i);
        swap(v , left , last);
        myqsort(v, left, last-1);
        myqsort(v, last+1, right);
    }
    /* swap: interchange v[i] and v[j] */
    void
    swap(char *v[], int i, int j)
    {
        char *temp;
        temp = v[i];
        v[i] = v[j];
        v[j] = temp;
    }

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/*宋宝华《Linux设备驱动程序开发详解》22.2中的关于GDB的使用小结*/
$编译pointer_array_try.c
    #gcc -g pointer_array_try.c -o pointer_array_try.
$运行gdb
    #gdb pointer_array_try.
$list命令
    (gdb)list -/list/l/list /list .
$run命令
    set args 设定运行参数;
    path

设定程序的运行路径;
    cd 改变工作目录;
    info terminal显示程序用到的终端信息.
$break命令
    break ;
    break ;
    break +offset/-offset;
    break filename:function;
    break *address;
    break 没有参数时表示下一行指令处停住;
    break if     eg.break if i=100.
$单步命令
    step   进入函数;
    next   不进入函数；
    set step-mode on/off
    finish 直到当前函数完成返回，并打印出返回时的堆栈地址和返回值等信息。是不是非常酷。
    until/u   运行程序直到退出循环体。
    setpi/si   nexti/ni    单步运行一条机器指令。
    display/i $pc
$continue命令
    continue [ignore-count]
    c [ignore-count]
    fg [ignore-count]       ignore-count表示忽略断点的个数
$print命令
    print
    print /
    p *array@len
$watch命令
    watch      expr有变化时停止运行程序
    rwatch     expr被读时停止
    awatch     expr被读或被写时停止
    info watchpoints
$examine命令
    examine/x /     number, format, units~~
$jump命令
    jump

$signal命令
    signal <1~15> UNIX系统信号量通常为1～15
$return命令
    return
    return
$call命令
    call
$info命令
    info regitsters  除开浮点寄存器
    info all-regitsters
    info regitsters
$disassemble命令
    disassemble