Shulou(Shulou.com)06/02 Report--

先上程序，该程序经过测试能够很好的实现写日志要求

/************************************************************************* > File Name: log.c > Author: ************************************************************************/#include #include #include #include #include #include #include #include #include int safe_asprintf(char **strp, const char *fmt, ...);int safe_vasprintf(char **strp, const char *fmt, va_list ap);void plog(const char *format, ...) ;void pinfo(const char *format, ...) ;#define DEBUG#ifdef DEBUGvoid plog(const char *format, ...);void pinfo(const char *format, ...);#define debug(fmt, args...) plog(fmt, ##args) #else#define debug(fmt, args...) do{}while(0)#endifstatic pthread_mutex_t fileMutex = PTHREAD_MUTEX_INITIALIZER;int main(int argc, char *argv){ return 0;}/* * safe_asprintf(); */int safe_asprintf(char **strp, const char *fmt, ...) { va_list ap; int retval; va_start(ap, fmt); retval = safe_vasprintf(strp, fmt, ap); va_end(ap); return retval;}/* * safe_vasprintf(); */int safe_vasprintf(char **strp, const char *fmt, va_list ap) { int retval; retval = vasprintf(strp, fmt, ap); if (retval == -1) { printf("Failed to vasprintf: %s. Bailing out\n", strerror(errno)); return 1; } return retval;}/* * plog(); */void plog(const char *format, ...) { pthread_mutex_lock(&fileMutex); FILE *fp = NULL; va_list vlist; char *fmt = NULL; // Open debug info output file. if (!(fp = fopen("log.txt", "a+"))) { pthread_mutex_unlock(&fileMutex); return; } va_start(vlist, format); safe_vasprintf(&fmt, format, vlist); va_end(vlist); if (!fmt) { pthread_mutex_unlock(&fileMutex); return; } time_t timep; struct tm *ptm = NULL; time(&timep); ptm = localtime(&timep); fprintf(fp, "[d-d-d-d-d-d] %s", ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday, ptm->tm_hour, ptm->tm_min, ptm->tm_sec, fmt); free(fmt); fsync(fileno(fp)); fclose(fp); pthread_mutex_unlock(&fileMutex);}/* * pinfo(); */void pinfo(const char *format, ...) { pthread_mutex_lock(&fileMutex); FILE *fp = NULL; va_list vlist; char *fmt = NULL; // Open debug info output file. if (!(fp = fopen("log.txt", "a+"))) { pthread_mutex_unlock(&fileMutex); return; } va_start(vlist, format); safe_vasprintf(&fmt, format, vlist); va_end(vlist); if (!fmt) { pthread_mutex_unlock(&fileMutex); return; } fprintf(fp, "%s", fmt); free(fmt); fsync(fileno(fp)); fclose(fp); pthread_mutex_unlock(&fileMutex);}

程序实现的日志格式为:

时间 + 空格 + 具体实现（自己的调试内容）

本段程序值得学习的地方:

va_list 结构体的使用linux 的格式化输出字符串文件操作过程中pthread_mutex锁的使用，以及他的优点linux DEBUG 的应用，方便调试

linux如何查看日志:

使用tail 命令可以实现日志的查询，以及其他功能，不了解的话，自行查资料解决。

对上面应用不明白的请自行查资料解决。

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