qiurui
/
glibc
mirror of git://sourceware.org/git/glibc.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix manual regarding switch from read to write on streams.

This commit is contained in:
Per Inge Mathisen 2011-05-11 23:43:26 -04:00 committed by Ulrich Drepper
parent e1fb097f44
commit 162ba701c2
2 changed files with 67 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
NEWS
View File

@ -11,9 +11,9 @@ Version 2.14
386, 11257, 11258, 11487, 11532, 11578, 11653, 11668, 11724, 11945, 11947, 386, 11257, 11258, 11487, 11532, 11578, 11653, 11668, 11724, 11945, 11947,
12158, 12178, 12200, 12346, 12393, 12420, 12445, 12449, 12454, 12460, 12158, 12178, 12200, 12346, 12393, 12420, 12445, 12449, 12454, 12460,
12469, 12489, 12509, 12510, 12518, 12541, 12545, 12551, 12583, 12587, 12469, 12489, 12509, 12510, 12518, 12527, 12541, 12545, 12551, 12583,
12597, 12611, 12625, 12631, 12650, 12653, 12655, 12660, 12681, 12685, 12587, 12597, 12611, 12625, 12631, 12650, 12653, 12655, 12660, 12681,
12711, 12713, 12714, 12717, 12723, 12734, 12738 12685, 12711, 12713, 12714, 12717, 12723, 12734, 12738
* The RPC implementation in libc is obsoleted. Old programs keep working * The RPC implementation in libc is obsoleted. Old programs keep working
but new programs cannot be linked with the routines in libc anymore. but new programs cannot be linked with the routines in libc anymore.

130
manual/stdio.texi
View File

@ -14,7 +14,7 @@ representing a communications channel to a file, device, or process.
@menu @menu
* Streams:: About the data type representing a stream. * Streams:: About the data type representing a stream.
* Standard Streams:: Streams to the standard input and output * Standard Streams:: Streams to the standard input and output
devices are created for you. devices are created for you.
* Opening Streams:: How to create a stream to talk to a file. * Opening Streams:: How to create a stream to talk to a file.
* Closing Streams:: Close a stream when you are finished with it. * Closing Streams:: Close a stream when you are finished with it.
* Streams and Threads:: Issues with streams in threaded programs. * Streams and Threads:: Issues with streams in threaded programs.
@ -26,17 +26,17 @@ representing a communications channel to a file, device, or process.
* Block Input/Output:: Input and output operations on blocks of data. * Block Input/Output:: Input and output operations on blocks of data.
* Formatted Output:: @code{printf} and related functions. * Formatted Output:: @code{printf} and related functions.
* Customizing Printf:: You can define new conversion specifiers for * Customizing Printf:: You can define new conversion specifiers for
@code{printf} and friends. @code{printf} and friends.
* Formatted Input:: @code{scanf} and related functions. * Formatted Input:: @code{scanf} and related functions.
* EOF and Errors:: How you can tell if an I/O error happens. * EOF and Errors:: How you can tell if an I/O error happens.
* Error Recovery:: What you can do about errors. * Error Recovery:: What you can do about errors.
* Binary Streams:: Some systems distinguish between text files * Binary Streams:: Some systems distinguish between text files
and binary files. and binary files.
* File Positioning:: About random-access streams. * File Positioning:: About random-access streams.
* Portable Positioning:: Random access on peculiar ISO C systems. * Portable Positioning:: Random access on peculiar ISO C systems.
* Stream Buffering:: How to control buffering of streams. * Stream Buffering:: How to control buffering of streams.
* Other Kinds of Streams:: Streams that do not necessarily correspond * Other Kinds of Streams:: Streams that do not necessarily correspond
to an open file. to an open file.
* Formatted Messages:: Print strictly formatted messages. * Formatted Messages:: Print strictly formatted messages.
@end menu @end menu
@ -186,13 +186,11 @@ but output is always appended to the end of the file.
@end table @end table
As you can see, @samp{+} requests a stream that can do both input and As you can see, @samp{+} requests a stream that can do both input and
output. The ISO standard says that when using such a stream, you must output. When using such a stream, you must call @code{fflush}
call @code{fflush} (@pxref{Stream Buffering}) or a file positioning (@pxref{Stream Buffering}) or a file positioning function such as
function such as @code{fseek} (@pxref{File Positioning}) when switching @code{fseek} (@pxref{File Positioning}) when switching from reading
from reading to writing or vice versa. Otherwise, internal buffers to writing or vice versa. Otherwise, internal buffers might not be
might not be emptied properly. The GNU C library does not have this emptied properly.
limitation; you can do arbitrary reading and writing operations on a
stream in whatever order.
Additional characters may appear after these to specify flags for the Additional characters may appear after these to specify flags for the
call. Always put the mode (@samp{r}, @samp{w+}, etc.) first; that is call. Always put the mode (@samp{r}, @samp{w+}, etc.) first; that is
@ -1109,17 +1107,17 @@ y_or_n_p (const char *question)
/* @r{Write a space to separate answer from question.} */ /* @r{Write a space to separate answer from question.} */
fputc (' ', stdout); fputc (' ', stdout);
/* @r{Read the first character of the line.} /* @r{Read the first character of the line.}
@r{This should be the answer character, but might not be.} */ @r{This should be the answer character, but might not be.} */
c = tolower (fgetc (stdin)); c = tolower (fgetc (stdin));
answer = c; answer = c;
/* @r{Discard rest of input line.} */ /* @r{Discard rest of input line.} */
while (c != '\n' && c != EOF) while (c != '\n' && c != EOF)
c = fgetc (stdin); c = fgetc (stdin);
/* @r{Obey the answer if it was valid.} */ /* @r{Obey the answer if it was valid.} */
if (answer == 'y') if (answer == 'y')
return 1; return 1;
if (answer == 'n') if (answer == 'n')
return 0; return 0;
/* @r{Answer was invalid: ask for valid answer.} */ /* @r{Answer was invalid: ask for valid answer.} */
fputs ("Please answer y or n:", stdout); fputs ("Please answer y or n:", stdout);
@} @}
@ -1328,7 +1326,7 @@ situation looks like this:
@smallexample @smallexample
f o o b a r f o o b a r
^ ^
@end smallexample @end smallexample
@noindent @noindent
@ -1340,7 +1338,7 @@ situation like this:
@smallexample @smallexample
f o o b a r f o o b a r
| |
o-- o--
^ ^
@end smallexample @end smallexample
@ -1354,7 +1352,7 @@ If you unread @samp{9} instead of @samp{o}, you get this situation:
@smallexample @smallexample
f o o b a r f o o b a r
| |
9-- 9--
^ ^
@end smallexample @end smallexample
@ -1527,19 +1525,19 @@ useful for printing error messages, tables of data, and the like.
@menu @menu
* Formatted Output Basics:: Some examples to get you started. * Formatted Output Basics:: Some examples to get you started.
* Output Conversion Syntax:: General syntax of conversion * Output Conversion Syntax:: General syntax of conversion
specifications. specifications.
* Table of Output Conversions:: Summary of output conversions and * Table of Output Conversions:: Summary of output conversions and
what they do. what they do.
* Integer Conversions:: Details about formatting of integers. * Integer Conversions:: Details about formatting of integers.
* Floating-Point Conversions:: Details about formatting of * Floating-Point Conversions:: Details about formatting of
floating-point numbers. floating-point numbers.
* Other Output Conversions:: Details about formatting of strings, * Other Output Conversions:: Details about formatting of strings,
characters, pointers, and the like. characters, pointers, and the like.
* Formatted Output Functions:: Descriptions of the actual functions. * Formatted Output Functions:: Descriptions of the actual functions.
* Dynamic Output:: Functions that allocate memory for the output. * Dynamic Output:: Functions that allocate memory for the output.
* Variable Arguments Output:: @code{vprintf} and friends. * Variable Arguments Output:: @code{vprintf} and friends.
* Parsing a Template String:: What kinds of args does a given template * Parsing a Template String:: What kinds of args does a given template
call for? call for?
* Example of Parsing:: Sample program using @code{parse_printf_format}. * Example of Parsing:: Sample program using @code{parse_printf_format}.
@end menu @end menu
@ -1561,7 +1559,7 @@ formatted and written to the output stream. For example,
int pct = 37; int pct = 37;
char filename[] = "foo.txt"; char filename[] = "foo.txt";
printf ("Processing of `%s' is %d%% finished.\nPlease be patient.\n", printf ("Processing of `%s' is %d%% finished.\nPlease be patient.\n",
filename, pct); filename, pct);
@end smallexample @end smallexample
@noindent @noindent
@ -2350,20 +2348,20 @@ make_message (char *name, char *value)
/* @r{Try to print in the allocated space.} */ /* @r{Try to print in the allocated space.} */
nchars = snprintf (buffer, size, "value of %s is %s", nchars = snprintf (buffer, size, "value of %s is %s",
name, value); name, value);
@end group @end group
@group @group
if (nchars >= size) if (nchars >= size)
@{ @{
/* @r{Reallocate buffer now that we know /* @r{Reallocate buffer now that we know
how much space is needed.} */ how much space is needed.} */
size = nchars + 1; size = nchars + 1;
buffer = (char *) xrealloc (buffer, size); buffer = (char *) xrealloc (buffer, size);
if (buffer != NULL) if (buffer != NULL)
/* @r{Try again.} */ /* @r{Try again.} */
snprintf (buffer, size, "value of %s is %s", snprintf (buffer, size, "value of %s is %s",
name, value); name, value);
@} @}
/* @r{The last call worked, return the string.} */ /* @r{The last call worked, return the string.} */
return buffer; return buffer;
@ -2452,7 +2450,7 @@ For example:
@smallexample @smallexample
#define myprintf(a, b, c, d, e, rest...) \ #define myprintf(a, b, c, d, e, rest...) \
printf (mytemplate , ## rest) printf (mytemplate , ## rest)
@end smallexample @end smallexample
@noindent @noindent
@ -2594,7 +2592,7 @@ For example, take this declaration of @code{eprintf}:
@smallexample @smallexample
void eprintf (const char *template, ...) void eprintf (const char *template, ...)
__attribute__ ((format (printf, 1, 2))); __attribute__ ((format (printf, 1, 2)));
@end smallexample @end smallexample
@noindent @noindent
@ -2781,30 +2779,30 @@ validate_args (char *format, int nargs, OBJECT *args)
int wanted; int wanted;
if (argtypes[i] & PA_FLAG_PTR) if (argtypes[i] & PA_FLAG_PTR)
wanted = STRUCTURE; wanted = STRUCTURE;
else else
switch (argtypes[i] & ~PA_FLAG_MASK) switch (argtypes[i] & ~PA_FLAG_MASK)
@{ @{
case PA_INT: case PA_INT:
case PA_FLOAT: case PA_FLOAT:
case PA_DOUBLE: case PA_DOUBLE:
wanted = NUMBER; wanted = NUMBER;
break; break;
case PA_CHAR: case PA_CHAR:
wanted = CHAR; wanted = CHAR;
break; break;
case PA_STRING: case PA_STRING:
wanted = STRING; wanted = STRING;
break; break;
case PA_POINTER: case PA_POINTER:
wanted = STRUCTURE; wanted = STRUCTURE;
break; break;
@} @}
if (TYPE (args[i]) != wanted) if (TYPE (args[i]) != wanted)
@{ @{
error ("type mismatch for arg number %d", i); error ("type mismatch for arg number %d", i);
return 0; return 0;
@} @}
@} @}
return 1; return 1;
@} @}
@ -2835,15 +2833,15 @@ The facilities of this section are declared in the header file
@menu @menu
* Registering New Conversions:: Using @code{register_printf_function} * Registering New Conversions:: Using @code{register_printf_function}
to register a new output conversion. to register a new output conversion.
* Conversion Specifier Options:: The handler must be able to get * Conversion Specifier Options:: The handler must be able to get
the options specified in the the options specified in the
template when it is called. template when it is called.
* Defining the Output Handler:: Defining the handler and arginfo * Defining the Output Handler:: Defining the handler and arginfo
functions that are passed as arguments functions that are passed as arguments
to @code{register_printf_function}. to @code{register_printf_function}.
* Printf Extension Example:: How to define a @code{printf} * Printf Extension Example:: How to define a @code{printf}
handler function. handler function.
* Predefined Printf Handlers:: Predefined @code{printf} handlers. * Predefined Printf Handlers:: Predefined @code{printf} handlers.
@end menu @end menu
@ -3010,7 +3008,7 @@ You should define your handler functions with a prototype like:
@smallexample @smallexample
int @var{function} (FILE *stream, const struct printf_info *info, int @var{function} (FILE *stream, const struct printf_info *info,
const void *const *args) const void *const *args)
@end smallexample @end smallexample
The @var{stream} argument passed to the handler function is the stream to The @var{stream} argument passed to the handler function is the stream to
@ -3058,7 +3056,7 @@ You have to define these functions with a prototype like:
@smallexample @smallexample
int @var{function} (const struct printf_info *info, int @var{function} (const struct printf_info *info,
size_t n, int *argtypes) size_t n, int *argtypes)
@end smallexample @end smallexample
The return value from the function should be the number of arguments the The return value from the function should be the number of arguments the
@ -3728,7 +3726,7 @@ conversion specification to read a ``variable assignment'' of the form
char *variable, *value; char *variable, *value;
if (2 > scanf ("%a[a-zA-Z0-9] = %a[^\n]\n", if (2 > scanf ("%a[a-zA-Z0-9] = %a[^\n]\n",
&variable, &value)) &variable, &value))
@{ @{
invalid_input_error (); invalid_input_error ();
return 0; return 0;
@ -4781,10 +4779,10 @@ provide equivalent functionality.
@menu @menu
* String Streams:: Streams that get data from or put data in * String Streams:: Streams that get data from or put data in
a string or memory buffer. a string or memory buffer.
* Obstack Streams:: Streams that store data in an obstack. * Obstack Streams:: Streams that store data in an obstack.
* Custom Streams:: Defining your own streams with an arbitrary * Custom Streams:: Defining your own streams with an arbitrary
input data source and/or output data sink. input data source and/or output data sink.
@end menu @end menu
@node String Streams @node String Streams
@ -4958,9 +4956,9 @@ and types described here are all GNU extensions.
@menu @menu
* Streams and Cookies:: The @dfn{cookie} records where to fetch or * Streams and Cookies:: The @dfn{cookie} records where to fetch or
store data that is read or written. store data that is read or written.
* Hook Functions:: How you should define the four @dfn{hook * Hook Functions:: How you should define the four @dfn{hook
functions} that a custom stream needs. functions} that a custom stream needs.
@end menu @end menu
@node Streams and Cookies @node Streams and Cookies