如果傳回值是INVALID_SET_FILE_POINTER,而且lpDistanceToMoveHigh不是NULL,則應用程式必須呼叫GetLastError來判斷函式是否成功或失敗。 下列程式代碼範例示範該案例。 C++ // Case One: calling the function with lpDistanceToMoveHigh == NULL// Try to move hFile file pointer some distanceDWORD dwPtr = SetFi...
如果返回值为INVALID_SET_FILE_POINTER并且lpDistanceToMoveHigh为非NULL,则应用程序必须调用GetLastError来确定函数是成功还是失败。 下面的代码示例演示了该方案。 C++ // Case One: calling the function with lpDistanceToMoveHigh == NULL// Try to move hFile file pointer some distanceDWORD dwPtr = SetFile...
file descriptor文件描述符 既然file是一种进程级别的资源,当一个进行打开多个文件时就需要对file进行管理,而linux内核中使用文件描述符来管理file资源,在linux内核中文件描述符为一个无符号整型,其管理采用数组方式,方便进行查询: 其中0,1和2进行了保留: 0: 标准输出standard input 1: 标准输入Output standard output...
NullPointerException iffdis null. Remarks Creates a file output stream to write to the specified file descriptor, which represents an existing connection to an actual file in the file system. First, if there is a security manager, itscheckWritemethod is called with the file descriptorfdObjargument...
When a file is opened, Windows associates a file pointer with the default stream. This file pointer is a 64-bit offset value that specifies the next byte to be read or the location to receive the next byte written. Each time a file is opened, the system places the file pointer at the...
文件流指针溢出--File Stream Pointer Overflows 概述 文件流指针溢出属于溢出利用方式的一种,主要存在于流函数(fopen(), fread(), fclose()等)。主要通过伪造在堆上的FILE结构体,覆盖结构体上的函数指针达到控制执行流的目的。 首先认识IO_FILE 结构体
Set the flags of the descriptor to the value specified by arg. O_APPEND, O_NONBLOCK, and O_ASYNC may be set; the other flags are unaffected. F_GETLK, F_SETLK, and F_SETLKW These commands are used to manage discretionary file locks. The third argument lock is a pointer to a struct ...
File identifier of an open file, specified as an integer. Before usingfseek, you must usefopento open the file and obtain its identifierfileID. Data Types:double Number of bytes to move fromorigin, specified as an integer. The value ofoffsetcan be positive, negative, or zero. ...
SetFilePointer( __in HANDLE hFile, __in LONG lDistanceToMove, __in_opt PLONG lpDistanceToMoveHigh, __in DWORD dwMoveMethod ); hFile是文件句柄。 lDistanceToMove是文件指针距离头或尾的长度。 lpDistanceToMoveHigh是文件指针距离头或尾的长度高位长度。
Close the file. fclose(fid); Input Arguments collapse all File identifier of an open file, specified as an integer. To open a file and obtain its identifier, use thefopenfunction. Data Types:double Extended Capabilities expand all Version History ...