[应用相关] 嵌入式软件中错误如何处理？

int func()

{

    int bIsErrOccur = 0;

    //do something that might invoke errors

    if(bIsErrOccur)  //Stage 1: error occurred

        return -1;   //Stage 2: generate error indicator

    //...

    return 0;

}



int main(void)

{

    if(func() != 0)  //Stage 3: detect error

    {

        //Stage 4: handle error

    }

    //Stage 5: recover or abort

    return 0;

}

if((p = malloc(100)) == NULL)

   //...



if((c = getchar()) == EOF)

   //...



if((ticks = clock()) < 0)

   //...

char *IntToAscii(int dwVal, char *pszRes, int dwRadix)

{

    if(NULL == pszRes)

        return "Arg2Null";



    if((dwRadix < 2) || (dwRadix > 36))

        return "Arg3OutOfRange";



    //...

    return pszRes;

}

typedef enum{

    S_OK,                   //成功

    S_ERROR,                //失败(原因未明确)，通用状态



    S_NULL_POINTER,         //入参指针为NULL

    S_ILLEGAL_PARAM,        //参数值非法，通用

    S_OUT_OF_RANGE,         //参数值越限

    S_MAX_STATUS            //不可作为返回值状态，仅作枚举最值使用

}FUNC_STATUS;



#define RC_NAME(eRetCode) \

    ((eRetCode) == S_OK                   ?    "Success"             : \

    ((eRetCode) == S_ERROR                ?    "Failure"             : \

    ((eRetCode) == S_NULL_POINTER         ?    "NullPointer"         : \

    ((eRetCode) == S_ILLEGAL_PARAM        ?    "IllegalParas"        : \

    ((eRetCode) == S_OUT_OF_RANGE         ?    "OutOfRange"          : \

      "Unknown")))))

extern int errno;

extern int *__errno_location(void);

#define errno (*__errno_location())

//调用库函数

if(返回错误值)

    //检查errno

if (somecall() == -1)

{

    printf("somecall() failed\n");

    if(errno == ...) { ... }

}

if (somecall() == -1)

{

    int dwErrSaved = errno;

    printf("somecall() failed\n");

    if(dwErrSaved == ...) { ... }

}

#include <string.h>

char *strerror(int errnum);

#include <stdio.h>

void perror(const char *msg);

int main(int argc, char** argv)

{

    errno = 0;

    FILE *pFile = fopen(argv[1], "r");

    if(NULL == pFile)

    {

        printf("Cannot open file '%s'(%s)!\n", argv[1], strerror(errno));

        perror("Open file failed");

    }

    else

    {

        printf("Open file '%s'(%s)!\n", argv[1], strerror(errno));

        perror("Open file");

        fclose(pFile);

    }



    return 0;

}

[wangxiaoyuan_[url=home.php?mod=space&uid=663872]@localhost[/url] test1]$ ./GlbErr /sdb1/wangxiaoyuan/linux_test/test1/test.c

Open file '/sdb1/wangxiaoyuan/linux_test/test1/test.c'(Success)!

Open file: Success

[wangxiaoyuan_@localhost test1]$ ./GlbErr NonexistentFile.h

Cannot open file 'NonexistentFile.h'(No such file or directory)!

Open file failed: No such file or directory

[wangxiaoyuan_@localhost test1]$ ./GlbErr NonexistentFile.h > test

Open file failed: No such file or directory

[wangxiaoyuan_@localhost test1]$ ./GlbErr NonexistentFile.h 2> test

Cannot open file 'NonexistentFile.h'(No such file or directory)!

int *_fpErrNo(void)

{

   static int dwLocalErrNo = 0;

   return &dwLocalErrNo;

}



#define ErrNo (*_fpErrNo())

#define EOUTOFRANGE  1

//define other error macros...



int Callee(void)

{

    ErrNo = 1;

    return -1;

}



int main(void)

{

    ErrNo = 0;

    if((-1 == Callee()) && (EOUTOFRANGE == ErrNo))

        printf("Callee failed(ErrNo:%d)!\n", ErrNo);

    return 0;

}

double Division(double fDividend, double fDivisor)

{

    return fDividend/fDivisor;

}

int main(void)

{

    int dwFlag = 0;

    if(1 == dwFlag)

    {

    RaiseException:

        printf("The divisor cannot be 0!\n");

        exit(1);

    }

    dwFlag = 1;



    double fDividend = 0.0, fDivisor = 0.0;

    printf("Enter the dividend: ");

    scanf("%lf", &fDividend);

    printf("Enter the divisor : ");

    scanf("%lf", &fDivisor);

    if(0 == fDivisor) //不太严谨的浮点数判0比较

        goto RaiseException;

    printf("The quotient is %.2lf\n", Division(fDividend, fDivisor));



    return 0;

}

[wangxiaoyuan_@localhost test1]$ ./test

Enter the dividend: 10

Enter the divisor : 0

The divisor cannot be 0!

[wangxiaoyuan_@localhost test1]$ ./test

Enter the dividend: 10

Enter the divisor : 2

The quotient is 5.00

CallerFunc()

{

    if((ret = CalleeFunc1()) < 0);

        goto ErrHandle;

    if((ret = CalleeFunc2()) < 0);

        goto ErrHandle;

    if((ret = CalleeFunc3()) < 0);

        goto ErrHandle;

    //...



    return;



ErrHandle:

    //Handle Error(e.g. printf)

    return;

}

#include <setjmp.h>

int setjmp(jmp_buf env);

void longjmp(jmp_buf env,int val);

jmp_buf gJmpBuf;

void Func1(){

    printf("Enter Func1\n");

    if(0)longjmp(gJmpBuf, 1);

}

void Func2(){

    printf("Enter Func2\n");

    if(0)longjmp(gJmpBuf, 2);

}

void Func3(){

    printf("Enter Func3\n");

    if(1)longjmp(gJmpBuf, 3);

}



int main(void)

{

    int dwJmpRet = setjmp(gJmpBuf);

    printf("dwJmpRet = %d\n", dwJmpRet);

    if(0 == dwJmpRet)

    {

        Func1();

        Func2();

        Func3();

    }

    else

    {

        switch(dwJmpRet)

        {

            case 1:

                printf("Jump back from Func1\n");

            break;

            case 2:

                printf("Jump back from Func2\n");

            break;

            case 3:

                printf("Jump back from Func3\n");

            break;

            default:

                printf("Unknown Func!\n");

            break;

        }

    }

    return 0;

}

dwJmpRet = 0

Enter Func1

Enter Func2

Enter Func3

dwJmpRet = 3

Jump back from Func3

jmp_buf gJmpBuf;

void RaiseException(void)

{

   printf("Exception is raised: ");

   longjmp(gJmpBuf, 1);  //throw，跳转至异常处理代码

   printf("This line should never get printed!\n");

}

double Division(double fDividend, double fDivisor)

{

    return fDividend/fDivisor;

}

int main(void)

{

    double fDividend = 0.0, fDivisor = 0.0;

    printf("Enter the dividend: ");

    scanf("%lf", &fDividend);

    printf("Enter the divisor : ");

    if(0 == setjmp(gJmpBuf))  //try块

    {

        scanf("%lf", &fDivisor);

        if(0 == fDivisor) //也可将该判断及RaiseException置于Division内

            RaiseException();

        printf("The quotient is %.2lf\n", Division(fDividend, fDivisor));

    }

    else  //catch块(异常处理代码)

    {

        printf("The divisor cannot be 0!\n");

    }



    return 0;

}

Enter the dividend: 10

Enter the divisor : 0

Exception is raised: The divisor cannot be 0!

#include <signal.h>

typedef void (*fpSigFunc)(int);

fpSigFunc signal(int signo, fpSigFunc fpHandler);

int raise(int signo);

void fphandler(int dwSigNo)

{

    printf("Exception is raised, dwSigNo=%d!\n", dwSigNo);

}

int main(void)

{

    if(SIG_ERR == signal(SIGFPE, fphandler))

    {

        fprintf(stderr, "Fail to set SIGFPE handler!\n");

        exit(EXIT_FAILURE);

    }



    double fDividend = 10.0, fDivisor = 0.0;

    if(0 == fDivisor)

    {

        raise(SIGFPE);

        exit(EXIT_FAILURE);

    }

    printf("The quotient is %.2lf\n", fDividend/fDivisor);



    return 0;

}

int main(void)

{

    if(SIG_ERR == signal(SIGFPE, fphandler))

    {

        fprintf(stderr, "Fail to set SIGFPE handler!\n");

        exit(EXIT_FAILURE);

    }



    int dwDividend = 10, dwDivisor = 0;

    double fQuotient = dwDividend/dwDivisor;

    printf("The quotient is %.2lf\n", fQuotient);



    return 0;

}

jmp_buf gJmpBuf;

void fphandler(int dwSigNo)

{

    printf("Exception is raised, dwSigNo=%d!\n", dwSigNo);

    longjmp(gJmpBuf, 1);

}

int main(void)

{

    if(SIG_ERR == signal(SIGFPE, SIG_DFL))

    {

        fprintf(stderr, "Fail to set SIGFPE handler!\n");

        exit(EXIT_FAILURE);

    }



    int dwDividend = 10, dwDivisor = 0;

    if(0 == setjmp(gJmpBuf))

    {

        double fQuotient = dwDividend/dwDivisor;

        printf("The quotient is %.2lf\n", fQuotient);

    }

    else

    {

        printf("The divisor cannot be 0!\n");

    }



    return 0;

}

#include <stdlib.h>

void exit(int status);

void _Exit(int status);

#include <unistd.h>

void _exit(int status);

int main(void)

{

    printf("Using exit...\n");

    printf("This is the content in buffer");

    exit(0);

    printf("This line will never be reached\n");

}

Using exit...

This is the content in buffer(结尾无换行符)

int main(void)

{

    printf("Using _exit...\n");

    printf("This is the content in buffer");

    fprintf(stdout, "Standard output stream");

    fprintf(stderr, "Standard error stream");

    //fflush(stdout);

    _exit(0);

}

Using _exit...

Standard error stream(结尾无换行符)

Using _exit...

Standard error streamThis is the content in bufferStandard output stream(结尾无换行符)

#include <stdlib.h>

int atexit(void (*func)(void));

double Division(double fDividend, double fDivisor)

{

    return fDividend/fDivisor;

}

void RaiseException1(void)

{

    printf("Exception is raised: \n");

}

void RaiseException2(void)

{

    printf("The divisor cannot be 0!\n");

}



int main(void)

{

    double fDividend = 0.0, fDivisor = 0.0;

    printf("Enter the dividend: ");

    scanf("%lf", &fDividend);

    printf("Enter the divisor : ");

    scanf("%lf", &fDivisor);

    if(0 == fDivisor)

    {

        atexit(RaiseException2);

        atexit(RaiseException1);

        exit(EXIT_FAILURE);

    }

    printf("The quotient is %.2lf\n", Division(fDividend, fDivisor));



    return 0;

}

Enter the dividend: 10

Enter the divisor : 0

Exception is raised: 

The divisor cannot be 0!

#include <stdlib.h>

void abort(void);

void abort(void)

{

    raise(SIGABRT);

    exit(EXIT_FAILURE);

}

#ifdef    NDEBUG

    #define assert(expr)        ((void) 0)

#else

    extern void __assert((const char *, const char *, int, const char *));

    #define assert(expr) \

        ((void) ((expr) || \

         (__assert(#expr, __FILE__, __LINE__, __FUNCTION__), 0)))

#endif

void __assert(const char *assertion, const char * filename,

              int linenumber, register const char * function)

{

    fprintf(stderr, " [%s(%d)%s] Assertion '%s' failed.\n",

            filename, linenumber,

            ((function == NULL) ? "UnknownFunc" : function),

            assertion);

    abort();

}

#undef assert

#ifdef NDEBUG

    #define assert(expr)        ((void) 0)

#else

    #define assert(expr)        ((void) ((expr) || \

         (fprintf(stderr, "[%s(%d)] Assertion '%s' failed.\n", \

         __FILE__, __LINE__, #expr), abort(), 0)))

#endif

char *Strcpy(char *pszDst, const char *pszSrc)

{

    char *pszDstOrig = pszDst;

    assert((pszDst != NULL) && (pszSrc != NULL));

    while((*pszDst++ = *pszSrc++) != '\0');

        return pszDstOrig;

}

FILE *OpenFile(const char *pszName, const char *pszMode)

{

    FILE *pFile = fopen(pszName, pszMode);

    assert(pFile != NULL);

    if(NULL == pFile)

        return NULL;



    //...

    return pFile;

}

int main(void)

{

    int dwChg = 0;

    assert(dwChg = 1);

    if(0 == dwChg)

        printf("Assertion should be enabled!\n");

    return 0;

}

pid_t Fork(void) //首字母大写，以区分系统函数fork()

{

    pid_t pid;

    if((pid = fork())<0)

    {

        fprintf(stderr, "Fork error: %s\n", strerror(errno));

        exit(0);

    }

    return pid;

}

#include <stdarg.h>

#include <syslog.h>

#define HAVE_VSNPRINTF  1

#define MAXLINE         4096  /* max text line length */

int daemon_proc;  /* set nonzero by daemon_init() */

static void err_doit(int errnoflag, int level, const char * fmt, va_list ap)

{

    int errno_save, n;

    char buf[MAXLINE + 1];



    errno_save = errno;    /* Value caller might want printed. */

#ifdef HAVE_VSNPRINTF

    vsnprintf(buf, MAXLINE, fmt, ap);

#else

    vsprintf(buf, fmt, ap);    /* This is not safe */

#endif

    n = strlen(buf);

    if (errnoflag) {

        snprintf(buf + n, MAXLINE - n, ": %s", strerror(errno_save));

    }

    strcat(buf, "\n");



    if (daemon_proc) {

        syslog(level, buf);

    } else {

        fflush(stdout);    /* In case stdout and stderr are the same */

        fputs(buf, stderr);

        fflush(stderr);

    }



    return;

}



void err_ret(const char * fmt, ...)

{

    va_list ap;



    va_start(ap, fmt);

    err_doit(1, LOG_INFO, fmt, ap);

    va_end(ap);



    return;

}