diff options
Diffstat (limited to '')
| -rw-r--r-- | man2/readv.2 | 48 |
1 files changed, 24 insertions, 24 deletions
diff --git a/man2/readv.2 b/man2/readv.2 index db6abbc..c1295cd 100644 --- a/man2/readv.2 +++ b/man2/readv.2 @@ -9,7 +9,7 @@ .\" add more details. .\" 2010-11-16, mtk, Added documentation of preadv() and pwritev() .\" -.TH readv 2 2023-05-03 "Linux man-pages 6.05.01" +.TH readv 2 2023-10-31 "Linux man-pages 6.7" .SH NAME readv, writev, preadv, pwritev, preadv2, pwritev2 \- read or write data into multiple buffers @@ -19,26 +19,26 @@ Standard C library .SH SYNOPSIS .nf .B #include <sys/uio.h> -.PP +.P .BI "ssize_t readv(int " fd ", const struct iovec *" iov ", int " iovcnt ); .BI "ssize_t writev(int " fd ", const struct iovec *" iov ", int " iovcnt ); -.PP +.P .BI "ssize_t preadv(int " fd ", const struct iovec *" iov ", int " iovcnt , .BI " off_t " offset ); .BI "ssize_t pwritev(int " fd ", const struct iovec *" iov ", int " iovcnt , .BI " off_t " offset ); -.PP +.P .BI "ssize_t preadv2(int " fd ", const struct iovec *" iov ", int " iovcnt , .BI " off_t " offset ", int " flags ); .BI "ssize_t pwritev2(int " fd ", const struct iovec *" iov ", int " iovcnt , .BI " off_t " offset ", int " flags ); .fi -.PP +.P .RS -4 Feature Test Macro Requirements for glibc (see .BR feature_test_macros (7)): .RE -.PP +.P .BR preadv (), .BR pwritev (): .nf @@ -57,7 +57,7 @@ buffers from the file associated with the file descriptor into the buffers described by .I iov ("scatter input"). -.PP +.P The .BR writev () system call writes @@ -67,7 +67,7 @@ buffers of data described by to the file associated with the file descriptor .I fd ("gather output"). -.PP +.P The pointer .I iov points to an array of @@ -75,19 +75,19 @@ points to an array of structures, described in .BR iovec (3type). -.PP +.P The .BR readv () system call works just like .BR read (2) except that multiple buffers are filled. -.PP +.P The .BR writev () system call works just like .BR write (2) except that multiple buffers are written out. -.PP +.P Buffers are processed in array order. This means that .BR readv () @@ -106,7 +106,7 @@ writes out the entire contents of before proceeding to .IR iov[1] , and so on. -.PP +.P The data transfers performed by .BR readv () and @@ -136,7 +136,7 @@ but adds a fourth argument, .IR offset , which specifies the file offset at which the input operation is to be performed. -.PP +.P The .BR pwritev () system call combines the functionality of @@ -149,7 +149,7 @@ but adds a fourth argument, .IR offset , which specifies the file offset at which the output operation is to be performed. -.PP +.P The file offset is not changed by these system calls. The file referred to by .I fd @@ -162,7 +162,7 @@ and calls, but add a fifth argument, .IR flags , which modifies the behavior on a per-call basis. -.PP +.P Unlike .BR preadv () and @@ -170,7 +170,7 @@ and if the .I offset argument is \-1, then the current file offset is used and updated. -.PP +.P The .I flags argument contains a bitwise OR of zero or more of the following flags: @@ -249,13 +249,13 @@ return the number of bytes read; and .BR pwritev2 () return the number of bytes written. -.PP +.P Note that it is not an error for a successful call to transfer fewer bytes than requested (see .BR read (2) and .BR write (2)). -.PP +.P On error, \-1 is returned, and \fIerrno\fP is set to indicate the error. .SH ERRORS The errors are as given for @@ -297,9 +297,9 @@ corresponding GNU C library wrapper functions shown in the SYNOPSIS. The final argument, .IR offset , is unpacked by the wrapper functions into two arguments in the system calls: -.PP +.P .BI " unsigned long " pos_l ", unsigned long " pos -.PP +.P These arguments contain, respectively, the low order and high order 32 bits of .IR offset . .SH STANDARDS @@ -329,12 +329,12 @@ POSIX.1-2001, .\" and \fIint\fP as the return type. .\" The readv/writev system calls were buggy before Linux 1.3.40. .\" (Says release.libc.) -.PP +.P .BR preadv (), .BR pwritev (): Linux 2.6.30, glibc 2.10. -.PP +.P .BR preadv2 (), .BR pwritev2 (): Linux 4.6, @@ -365,7 +365,7 @@ The wrapper function for .BR writev () performed the analogous task using a temporary buffer and a call to .BR write (2). -.PP +.P The need for this extra effort in the glibc wrapper functions went away with Linux 2.2 and later. However, glibc continued to provide this behavior until glibc 2.10. @@ -405,7 +405,7 @@ flag may return 0 even when not at end of file. .SH EXAMPLES The following code sample demonstrates the use of .BR writev (): -.PP +.P .in +4n .EX char *str0 = "hello "; |