dlopen.3: tfix

[thirdparty/man-pages.git] / man2 / pread.2

diff --git a/man2/pread.2 b/man2/pread.2
index 18eae6a71dcc1c39f42a4b77c77100f043d0f11f..edd8bb3e9b1b5f04675d6b1f131f4488e07e0e2e 100644 (file)
--- a/man2/pread.2
+++ b/man2/pread.2
@@ -22,25 +22,25 @@
 .\" the source, must acknowledge the copyright and authors of this work.
 .\" %%%LICENSE_END
 .\"
-.TH PREAD 2 2013-06-21 "Linux" "Linux Programmer's Manual"
+.TH PREAD 2 2017-09-15 "Linux" "Linux Programmer's Manual"
 .SH NAME
 pread, pwrite \- read from or write to a file descriptor at a given offset
 .SH SYNOPSIS
 .B #include <unistd.h>
-.sp
+.PP
 .BI "ssize_t pread(int " fd ", void *" buf ", size_t " count \
 ", off_t " offset );
-.sp
+.PP
 .BI "ssize_t pwrite(int " fd ", const void *" buf ", size_t " count \
 ", off_t " offset );
-.sp
+.PP
 .in -4n
 Feature Test Macro Requirements for glibc (see
 .BR feature_test_macros (7)):
 .in
+.PP
 .PD 0
 .ad l
-.sp
 .BR pread (),
 .BR pwrite ():
 .RS 4
@@ -77,15 +77,23 @@ The file referenced by
 .I fd
 must be capable of seeking.
 .SH RETURN VALUE
-On success, the number of bytes read or written is returned (zero
-indicates that nothing was written, in the case of
-.BR pwrite (),
-or
-end of file, in the case of
-.BR pread ()),
-or \-1 on error, in which case
+On success,
+.BR pread ()
+returns the number of bytes read
+(a return of zero indicates end of file)
+and
+.BR pwrite ()
+returns the number of bytes written.
+.PP
+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
+On error, \-1 is returned and
 .I errno
-is set to indicate the error.
+is set to indicate the cause of the error.
 .SH ERRORS
 .BR pread ()
 can fail and set
@@ -113,7 +121,7 @@ C library support (including emulation using
 .BR lseek (2)
 on older kernels without the system calls) was added in glibc 2.1.
 .SH CONFORMING TO
-POSIX.1-2001.
+POSIX.1-2001, POSIX.1-2008.
 .SH NOTES
 The
 .BR pread ()
@@ -123,7 +131,7 @@ system calls are especially useful in multithreaded applications.
 They allow multiple threads to perform I/O on the same file descriptor
 without being affected by changes to the file offset by other threads.
 .\"
-.SS C library/kernel ABI differences
+.SS C library/kernel differences
 On Linux, the underlying system calls were renamed
 in kernel 2.6:
 .BR pread ()
@@ -139,7 +147,7 @@ The glibc
 and
 .BR pwrite ()
 wrapper functions transparently deal with the change.
-
+.PP
 On some 32-bit architectures,
 the calling signature for these system calls differ,
 for the reasons described in