gdb.info: open

open

Synopsis:
     int open(const char *pathname, int flags);
     int open(const char *pathname, int flags, mode_t mode);

Request:
     Fopen,pathptr/len,flags,mode

`flags' is the bitwise or of the following values:

`O_CREAT'
     If the file does not exist it will be created.  The host rules
     apply as far as file ownership and time stamps are concerned.

`O_EXCL'
     When used with O_CREAT, if the file already exists it is an error
     and open() fails.

`O_TRUNC'
     If the file already exists and the open mode allows writing
     (O_RDWR or O_WRONLY is given) it will be truncated to length 0.

`O_APPEND'
     The file is opened in append mode.

`O_RDONLY'
     The file is opened for reading only.

`O_WRONLY'
     The file is opened for writing only.

`O_RDWR'
     The file is opened for reading and writing.

     Each other bit is silently ignored.

`mode' is the bitwise or of the following values:

`S_IRUSR'
     User has read permission.

`S_IWUSR'
     User has write permission.

`S_IRGRP'
     Group has read permission.

`S_IWGRP'
     Group has write permission.

`S_IROTH'
     Others have read permission.

`S_IWOTH'
     Others have write permission.

     Each other bit is silently ignored.

Return value:
     open returns the new file descriptor or -1 if an error
     occured.

Errors:

`EEXIST'
     pathname already exists and O_CREAT and O_EXCL were used.

`EISDIR'
     pathname refers to a directory.

`EACCES'
     The requested access is not allowed.

`ENAMETOOLONG'
     pathname was too long.

`ENOENT'
     A directory component in pathname does not exist.

`ENODEV'
     pathname refers to a device, pipe, named pipe or socket.

`EROFS'
     pathname refers to a file on a read-only filesystem and write
     access was requested.

`EFAULT'
     pathname is an invalid pointer value.

`ENOSPC'
     No space on device to create the file.

`EMFILE'
     The process already has the maximum number of files open.

`ENFILE'
     The limit on the total number of files open on the system has been
     reached.

`EINTR'
     The call was interrupted by the user.