#Python file peek usage portable

#Python file peek usage portable

POSIX.1-2001 allows eitherĮrror to be returned for this case, and does not require these constants to have the same value, so a portable application should check for both possibilities.ĮBADF fd is not a valid file descriptor or is not open for reading.ĮFAULT buf is outside your accessible address space.ĮINTR The call was interrupted by a signal before any data was read see signal(7).ĮINVAL fd is attached to an object which is unsuitable for reading or the file was opened with the O_DIRECT flag, and either the address specified

In this case it is left unspecified whether theĮrrors EAGAIN The file descriptor fd refers to a file other than a socket and has been marked nonblocking ( O_NONBLOCK), and the read would block.ĮAGAIN or EWOULDBLOCK The file descriptor fd refers to a socket and has been marked nonblocking ( O_NONBLOCK), and the read would block. On error, -1 is returned, and errno is set appropriately. It is not an error if this number is smaller than the number of bytes requested this may happen for example because fewerīytes are actually available right now (maybe because we were close to end-of-file, or because we are reading from a pipe, or from a terminal), or because On success, the number of bytes read is returned (zero indicates end of file), and the file If count is greater than SSIZE_MAX, the result is unspecified. In the absence of any errors, or if read() does not check forĮrrors, a read() with a count of 0 returns zero and has no other effects.

If count is zero, read() may detect the errors described below.

The current file offset is at or past the end of file, no bytes are read, and read() returns zero. On files that support seeking, the read operation commences at the current file offset, and the file offset is incremented by the number of bytes read. Read() attempts to read up to count bytes from file descriptor fd into the