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ООО "Хи-Квадрат", ИНН 7718990614
readv - read a vector
#include <sys/uio.h>
ssize_t readv(int fildes, const struct iovec *iov,
int iovcnt);
The readv() function shall be equivalent to read(), except as described below. The readv() function shall place the input data into the iovcnt buffers specified by the members of the iov array: iov[0], iov[1], ..., iov[ iovcnt-1]. The iovcnt argument is valid if greater than 0 and less than or equal to {IOV_MAX}.
Each iovec entry specifies the base address and length of an area in memory where data should be placed. The readv() function shall always fill an area completely before proceeding to the next.
Upon successful completion, readv() shall mark for update the st_atime field of the file.
Refer to read() .
In addition, the readv() function shall fail if:
The readv() function may fail if:
The following sections are informative.
The following example reads data from the file associated with the file descriptor fd into the buffers specified by members of the iov array.
#include <sys/types.h> #include <sys/uio.h> #include <unistd.h> ... ssize_t bytes_read; int fd; char buf0[20]; char buf1[30]; char buf2[40]; int iovcnt; struct iovec iov[3]; iov[0].iov_base = buf0; iov[0].iov_len = sizeof(buf0); iov[1].iov_base = buf1; iov[1].iov_len = sizeof(buf1); iov[2].iov_base = buf2; iov[2].iov_len = sizeof(buf2); ... iovcnt = sizeof(iov) / sizeof(struct iovec); bytes_read = readv(fd, iov, iovcnt); ...
read() , writev() , the Base Definitions volume of IEEE Std 1003.1-2001, <sys/uio.h>
