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READV(3) Linux Programmer's Manual READV(3) NAME readv, writev - read or write data into multiple buffers SYNOPSIS #include <sys/uio.h> int readv(int filedes, const struct iovec *vector, size_t count); int writev(int filedes, const struct iovec *vector, size_t count); DESCRIPTION The readv() function reads count blocks from the file associated with the file descriptor filedes into the multiple buffers described by vec- tor. The writev() function writes at most count blocks described by vector to the file associated with the file descriptor filedes. The pointer vector points to a struct iovec defined in <sys/uio.h> as struct iovec { void *iov_base; /* Starting address */ size_t iov_len; /* Number of bytes */ }; Buffers are processed in the order vector[0], vector[1], ... vec- tor[count]. The readv() function works just like read(2) except that multiple buf- fers are filled. The writev() function works just like write(2) except that multiple buffers are written out. RETURN VALUE The readv() function returns the number of bytes or -1 on error; the writev() function returns the number of bytes written. ERRORS The readv() and writev() functions can fail and set errno to the fol- lowing values: EBADF fd is not a valid file descriptor. EINVAL fd is unsuitable for reading (for readv()) or writing (for writev()). EFAULT buf is outside the processes' address space. EAGAIN Non-blocking I/O had been selected in the open() call, and read- ing or writing could not be done immediately. EINTR Reading or writing was interrupted before any data was trans- ferred. CONFORMING TO unknown BUGS It is not advisable to mix calls to functions like readv() or writev(), which operate on file descriptors, with the functions from the stdio library; the results will be undefined and probably not what you want. SEE ALSO read(2), write(2) GNU 1993-04-25 READV(3)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | BUGS | SEE ALSO
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