CRTL, open, Arguments
*Conan The Librarian
file_spec A null-terminated character string containing a valid file specification. If you specify a directory in the file_spec and it is a search list that contains an error, Compaq C interprets it as a file open error. flags The following values are defined in the <file.h> header file: O_RDONLY Open for reading only O_WRONLY Open for writing only O_RDWR Open for reading and writing O_NDELAY Open for asynchronous input O_APPEND Append on each write O_CREAT Create a file if it does not exist O_TRUNC Create a new version of this file O_EXCL Error if attempting to create existing file These flags are set using the bitwise OR operator (|) to separate specified flags. Opening a file with O_APPEND causes each write on the file to be appended to the end. (In contrast, with the VAX C RTL the behavior of files opened in append mode was to start at EOF and, thereafter, write at the current file position.) If O_TRUNC is specified and the file exists, open creates a new file by incrementing the version number by 1, leaving the old version in existence. If O_CREAT is set and the named file does not exist, the Compaq C RTL creates it with any attributes specified in the fourth and subsequent arguments ( . . . ). If O_EXCL is set with O_CREAT and the named file exists, the attempted open returns an error. mode An unsigned value that specifies the file-protection mode. The compiler performs a bitwise AND operation on the mode and the complement of the current protection mode. You can construct modes by using the bitwise OR operator (|) to separate specified modes. The modes are: 0400 OWNER:READ 0200 OWNER:WRITE 0100 OWNER:EXECUTE 0040 GROUP:READ 0020 GROUP:WRITE 0010 GROUP:EXECUTE 0004 WORLD:READ 0002 WORLD:WRITE 0001 WORLD:EXECUTE The system is given the same access privileges as the owner. A WRITE privilege also implies a DELETE privilege. . . . Optional file attribute arguments. The file attribute arguments are the same as those used in the creat function. For more information, see the creat function.